Are you looking for a more cantankerous version of this video where I go over more of the experimental design, with 138% more runtime and 75% more snark? Then the main channel video's got you covered! th-cam.com/video/DTsQjiPlksA/w-d-xo.html
@@linuxgeex Nah. For one, you're missing that the design conditions only showed up for ~36 hours total this year. And when we're talking about heat pumps, where the compressor only gets lubrication when it's running, shorter cycles are actually _bad_ for them. Short-cycling kills equipment, and that's what my furnace is doing all the time. It's less bad for the furnace, to be sure, but it's absolute hell on a compressor. And as I said - you need to get comfortable with there being secondary heat sources. That provides the margin.
Any chance you might be able to do an HVAC video on apartment heating and cooling? I.E. more specifically HVAC where you're not allowed to make any physical changes to walls or ducting, and or perhaps options for heat pump style window heating/cooling systems. I know you did a video on portable air conditioners and your hate for them, but perhaps more on figuring out what kind of output you need based on the size of the apartment, and perhaps on window units that actually function as a heat pump since there are a few that do.
The efficiency of smaller heatpumps are higher reaching a COP of 5 at the rated output than larger ones are going to be closer too 3 or 4 at best. The reason for this is that not everything is suitably upsized and therefore the efficiency suffers. But what is the COP when not running hard out??? Turn out if running lightly while these numbers are never published a larger heatpump running on low power can have a COP well above 5! And so the more hard out a heat-pump has to run the more you pay for the same heating (or cooling).
I am very impressed how Alec didn't just chop pieces of the video out, but wrote and produced a seemingly almost completely separate script and filming session.
I was initially just going to put this on with the volume down to give him the algorithm boost of engagement and watch time, but then I realized that it does, indeed, appear to be a whole new (if _very_ similar) video!
I’m so glad you made this condensed version, I love the big main video but it would be overwhelming to my mom who plans to get an AC unit to replace her swamp cooler and I’ve been trying to talk her into getting a heat pump
Yeah this mid-length is great for sharing... and putting it on a different channel is the right move. I really wish TH-cam would allow channels to publish multiple sub-channels so we could separately subscribe to topics and formats... for the most part I would use it to avoid the Shorts... like Integza putting out 3 related "I did a " Shorts a year or more after the video they reference. Ugh! So yeah, this channel is awesome, and if you do Shorts, please make them a 3rd channel.
@@RomanShein1978 I immediately switched here when he pointed out the length of the main video, and even 26 minutes is longer than I normally prefer for single-topic videos. But his content is always worth the time.
Good luck, I thought I had convinced my parents on installing heat pumps for their home remodel, but they balked once they got quotes from some HVAC contractors. It's a huge missed opportunity in futureproofing, as we live in the Bay Area where we don't need much heating capacity and where some cities have started phasing out gas appliances.
I just went through this in the last two years. I had a ~75,000 BTU furnace and a 4 ton AC. It was time to replace and everyone wanted to replace with same same or go bigger. I finally found an HVAC contractor that did the calculations and showed his homework to prove it. Taking into account all my home upgrades, he calculated that I only needed a 40,000 BTU and a 2 ton AC. I was very skeptical but the math doesn't lie. This saved me a bunch of money and I was able to change my 40 AMP breaker for AC to a 20 AMP. It continues to save me money on my electric bill. You are right, on the coldest and hottest days it runs just about constantly. BUT IT IS DESIGNED THAT WAY. And those extremes are only a very few days a year. Make your HVAC contractor do the Manual J and make them show you their homework. Most will just walk away because they don't want to do the work. Those are contractors you don't want working for you anyway.
A smaller unit shouldn’t save (much) money on your electric bill; it still has to do the same amount of work, just spread over a longer period. (Yes, there are some losses due to a larger unit short cycling, but they shouldn’t be significant.)
@@k5sss assuming a single-speed compressor rather than 2-stage or variable speed compressor, and assuming the same runtime (work-hours) smaller unit draws far less current when it's running than the larger unit. a larger unit with variable speed should be comparable to the single-speed smaller unit in this example though right?
@@Robin-xe4yzIf the larger unit is drawing more power, then it’s running for proportionately less time, so the total work done is (about) the same. Multi-stage and variable-speed units are designed to act like a smaller unit when that’s all that’s needed. That prevents short cycling but doesn’t change the total work being done.
There was a *125,000* BTU/hr gas furnace installed in my ~1800 sq ft house when I bought it. It was replaced with a 70,000 BTU/hr two stage furnace that almost never runs on the second stage. The only time stage 2 was necessary was the day after you mentioned in 2022 when we got the same cold blast in Ohio. Even then it didn’t run full blast for more than a couple hours. Yep, my system was also oversized by 3-4x!
Our ~1900 sq ft house currently has a 115,000 BTU/hr gas furnace. The longest it has ever run in the winter during a single 24hr period was for 9hrs when the outdoor temp averaged 8 degrees Fahrenheit. Definitely overkill.
My apartment's maintenance guy is overworked and busy as hell, but thankfully he's an ABSOLUTE DORK about stuff like this. Just did this for our water heaters (i hear he vetoed the company's idea for on-demand heaters,) AND solved the moisture problem in our basements by putting condensers on them. The world needs more folks like him.
You having any hot water issues or weird symptoms? Our basement was way more humid when our venting seemed to be working the worst and it was hard to recognize it was from lack of air and/or some vent restriction. When symptoms were worst for us, it was way more humid than normal in the basement room w/ it and the only time winter humidity was a problem for us. The combustion exhaust apparently has quite a lot of water, even for the low output of a 36k BTU water heater, and it made a huge difference when I'm pretty positive it wasn't venting properly if at all. When it worked normally, there wasn't any real humidity introduced and there shouldn't be
@@Demoralized88 We're all electric with no central heating or anything, so I'm not sure our stuff applies to your situation. Also, I'd have to ask Dave, I don't know much about troubleshooting anything that doesn't have an operating system 🤣
One note of caution on kill-a-watt style energy monitors... they usually aren't designed to actually be able to handle high wattages for hours at a time. They tend to overheat and start melting the plastic casing. The problem isn't the shunt, instead it is the typically low-grade plug receptacle. I had this happen to one of mine while I was monitoring a mere 700W of power for 4-5 hours a day. After about a month I took it out and realized that the plug was somewhat stuck in the receptacle and the plastic looked a bit melted and brown on the unit. It hadn't caught fire but the plastic obviously over-heated. I ripped the sucker apart so I could get a good look, and It turned out to be oxidation of the contacts in the plug receptacle combined with relatively flimsy contacts. The area the unit has been installed in was clean, but the low quality of the device meant the manufacturer had cut corners. I no longer use my kill-a-watts to measure high amounts of power unattended. -Matt
@@superslash7254that's great to know about. The other option is something like Emporia, installed in the main panel with multiple non-contact sensors (CTs) to monitor multiple circuits.
Most people aren't going to understand this, but for a Midwesterner, that Google rant was _pure unmitigated rage._ I'm surprised his hair didn't catch fire or something.
Wait is that a Midwest thing? I so heavily just *felt* that frustration but I thought that was an everyone thing? Please enlighten me I'd love to know about this.
The thing you learn by watching the Home Performance channel on TH-cam is that heating and cooling is only one dimension of the problem, and that taking care of the humidity is a second dimension that many people don't know about, much less do anything to address. And humidity can lead to huge problems in many areas, including mold and mildew growth, which can be a huge health problem. I'm glad you touch on it in this video, and doing a Manual J calculation, but I'd like to see you talk more about how important it is to control humidity.
I can one up you on this one big time. I just bought a home in Sonoma County (about an hour north of SF in California). Even being a 1940's home with no attic or crawl space insulation, Manual J calls for about 32,000BTU of heating need. Drops well below 2 tons once the crawl space is addressed, and down to about 1.5 tons when the attic is sorted. Someone actually installed an 84,000BTU furnace on this house... it was so oversized that there is evidence that it caught itself on fire at one point. There was a 90 degree temperature delta (Furnace was blowing 155 degree air when inside temps were 65 inside the house). The only reason I noticed it was so bad was I switched out my battery powered thermostat for an Ecobee which takes its power from the C wire. The furnace was tripping its own overheat sensor every 20 minutes and shutting down the thermostat. People really need to know more about the basics of HVAC, what Manual J is, and the benefits of heat pumps. People also need to know enough to ask questions of their HVAC professionals, there are a lot of very smart, very good people out there doing good work... there are also a lot of folks who measure with their thumbs and are more interested in being done in a single day and never having to come back rather than doing a good job...
I have the same issue, our house is 1200 sq ft. and the last owner had an HVAC professional install a 60,000 BTU furnace for this small house, completely overkill. I installed an ecobee and the same thing happened to me, it would restart everytime the heat turned on it felt like. I had an HVAC tech out to take a look and they advised me that the furnace is WAY too large for the house and that eventually my heat exchanger will crack and fail due to the system overheating constantly. I'm in Ontario Canada, but even here it feels like the winters are getting milder and milder. So now I need to shell out for a new smaller furnace or just bite the bullet and install an appropriately sized heat pump instead.
@@Airseas TL;DR find a professional who understands heat pumps/Manual J load calculations and ask them about retrofitting your system for dual fuel and setting your furnace changeover point to a very low temperature (a really good tech will be able to recommend that temperature based on your region and gas vs. electric energy costs). The long story: Check out the rest of his HVAC videos. All the info is really great. You don't need to replace your furnace, you can get an appropriately sized heat pump (outside unit) and put an A-coil on your furnace and just use the furnace as an air handler. Gree makes a pretty affordable inverter heat pump that can be field installed as 2 or 3 tons that is designed to work with mismatched air handlers (it uses the temperature of the refrigerant as it comes back to the outside unit to vary how much output its sending). It's still not "cheap" and if you have a good/newish Air Conditioner then you are still stuck replacing something expensive... but if you happen to have an old AC ready to be replaced then this is a pretty cost effective way to adapt your oversized furnace to a much more efficient heat pump system. It'll never be as efficient as a fully matched heat pump/air handler/thermostat from like Mitsubishi or Fujitsu... but considering how much less it would cost to install, I think you'd still come out ahead until it's time to really put in a new system in 15-30 years. The unit I referenced is the Gree Flex (aka GE Connect aka Mr. Cool Universal). My house has a GE Connect using the 17 year old furnace as a vestige air handler (we had the gas line turned off). We never get below 25 degrees outside, so ymmv but it never runs more than 1 hour a day here so even IT is oversized for us.
Not only was your furnace oversized, but apparently the duct work was way undersized for that furnace as well. Probably noisy too. A 90 degree delta for a scorched air system is about as unprofessional as it gets.
@@jamesnasium7036 yeah it was pretty bad. Luckily the previous owners had installed a heat pump as an air conditioner only. Got someone to come rewire it for heating and cooling and we are using that ridiculous furnace as an air handler. It’s not perfect but it’s safe and works a hell of a lot better.
I had to basically beg my HVAC installer to put in an undersized furnace when we upgraded from gas furnace+AC to gas furnace+heat pump. "Don't worry, in winter, the top floor stays plenty hot from heat rising, we'll shut off the vents to the top floor in Winter; likewise the basement stays way too cool in the summer, we'll shut it off. It'll only be heating/cooling 2/3 of the total volume of the house at any time." He finally agreed. And then we got a free upgrade (not in capacity, but in capability) because Lennox became so backordered they couldn't deliver the smaller-capacity, medium-capability one we wanted. So instead of a 2-phase, we got an "variable phase" (aka: it can produce exactly the heat/cooling level needed, instead of "FULL BLAST FOR A FEW MINUTES then off.")
I just noted this same consideration..... that systems can be had, and likely will become more developed out; that modulate the output to the granular data going in..
@@gg-gn3re That would be nice if zoned HVAC could do that. All I have are manual baffles in the utility room to enable/disable the registers in the basement and top floor. (Separate baffles for the two floors - the main floor stays open at all times.) I know there are more granular zoned systems, or even multi-mini-split systems that can move refrigerant between rooms to do that, but they’re expensive.
@@AnonymousFreakYTYea they are, I was being literal. Run a separate duct entirely from your system and then just have some switch to turn it on/off it's likely you'd want it on almost 24/7 so I'd just run it separate. As you say there are systems that can handle this kinda thing but they're 10x the price
As an HVAC-R technician, thank you for pointing out these issues that this industry needs to address by training techs to do manual J, sizing equipment properly, and not being salesmen first, would do so much to help move the industry forward in a more efficient direction. I'm working on starting my own business this year (hopefully), and I have the same mentality as you, more pumping, more now, at reasonable prices.
@rogerk6180 While that may be true, by offering more efficient units and service, you would, in the long run, earn more from repeat customers rather than the highway robbery some companies are responsible for these days. I see what the company I work for charges for almost every job I run, and it's nauseating at best what they get away with charging in most cases.
@rogerk6180 It's the mindset that needs to change, and unfortunately, that's far easier said than done. That's why I hope to make a small ripple in the big pond of companies in my industry, it might not do much, but it could start things moving in the right direction if enough people start talking about it.
@@joshengelbrecht1310 the problem is people no longer want to know anything anymore. All they know is more bigger and more expensive is better and having more expensive is more bragging power. Picking the cheaper option must mean it is worse or it makes you a cheapskate. So the one who offers you the biggest and more expensive option must be the better option. And companies are more then willing to accomodate that. In the past people had at least some superficial knowledge about most things and thus knew what they needed and where looking for. Most people can't even put up a lightbulb anymore it seems and are so conditioned that everything is some complicated safety risk that it needs some high payed profesional to do it. Even though most things are done by random dudes that are sent over as a profesional that barely know the right end of a screwdriver themselves. I see a lot of americans moving to the netherlands where i live, and how many basic home tasks they request a "contractor" for that are just simple things every single person here knows how to do themselves in 15 minutes is shocking. I imagine your grandparrents did these things themselves around the house as well, but somehow culture shifted where this skill was lost or made to look so scary that people are de-incentivised from doing them themselves. The amount of light fixtures i put up and shower heads i have replaced for bewildered american neighbours is just shocking lol. That is something your dad teaches you how to do when he does it at home or the first time you move out of the house here in the netherlands. There is a cultural difference for sure. Ignorance breeds exploitation. If you have no idea what a job actually entails and seems mighty difficult you can basicly ask what you want to do it for other people.
As an hvac master myself, in upstate NY, a lot of manual J up here are way undersized lol. Not the other way around. I had one set of plans with Emmanuel J that said they needed a 40000 BTU furnace for 1600 square feet of house. Yeah right. You're not taking into consideration air exchanges, dehumidification, and enthalpy. I do see a lot of oversized equipment out there though. Good video!
I'm in Canada and love my cold climate heat pump. We have 15 kW of backup heat strips which I'm now thinking are wayoverkill and they have yet to be used despite outdoor temps dropping to below -30 last year. They definitely didn't get used this year as we barely had winter. Heat pumps are amazing. Highly recommend!
One other thing that cannot be understated is air leakage and window radiation, and how much of a dramatic difference it can make to the heating or cooling efficiency of your home. We live in a more mild climate and only have a reverse cycle air conditioner in our home (a.k.a. a heat pump). I reduced my power bills by at least 20% month for month from one year to the next by only adding tinting on the east and western facing windows along with redoing all the air seals on all the windows and the external doors and actually adding one to the attached garage. A downside to living in Australia is that a LOT of buildings over just do not take thermal efficiency into account and the building codes reflect that mindset.
Thank you so much for producing this video (and all your others too)! The shorter format, specifically designed for sharing is particularly useful. My 1100sqft 1940s single story house in a mild/moderate California climate came with a 3ton 36kBTU gas furnace, which only heated half the house in short bursts. Fast forward 7 years, $15k in overpriced “guesstimate sized” hvac with new ducts to the rest of the house, installed in a day, and was never commissioned correctly… and my home was still uncomfortable. As an experiment, two years ago I DIY installed a 1-ton 12kBTU VRF mini-split heat pump in the central room of the house and it’s capable of handling ALL MY HEATING AND COOLING NEEDS! It keeps my house comfy at 69degrees, and does so using 700-1000watts, near silently, and cost me < $1000 to DIY install (including buying all the tools). The $15k 3ton gas furnace with 14 SEER heat-pump system could technically sit idle or be removed. @Technology Connections - Ideas for followup videos - air sealing / insulation - oversized MERV 13-16 filters - IAQ - radon, CO2, particulates (PM2.5) I’ve fallen down a deep rabbit hole of knowledge that typical hvac installers are not trained/educated about. Thank you again for putting out all this content. The residential HVAC industry needs to get learning and implementing best practices quickly, so we can collectively move away from burning things for heat, save money, and all live more comfortable/healthy.
Hot water baseboard system here, in northern Pennsylvania. Temps rarely get below 0°F and VERY rarely down to -15°. The old system was a 140k BTU monster and maybe in the 70% efficiency range. We replaced the windows, reinsulated the walls, and added insulation in about 2/3 of the attic; the new boiler is 90% efficiency 80k BTU, and also heats the domestic hot water. If one or both of the thermostats are calling for heat (and the HW tank isn't), it checks the outdoor temp, and the water temp coming back from the house on the return side, and does some of that "math" stuff to determine how hot the output water should be, and fires the modulated burner accordingly. When it was first set up, with a low-end design temp of -15°, on a 0° but windy night, it couldn't keep up - the temperature curve had it still holding back a little at 0°, and the house couldn't get above about 63-65°. I reprogrammed the curve to ramp up to full throttle as it approaches 0° instead, and that did the trick.
I worked in the oil heat industry for many years. Everything you said is exactly what we attempted to teach our customers. We always did load calculations and more times than not recommended replacing old units with smaller more efficient units. People have been brainwashed that "bigger is better". Design load is immensely important, especially for cooling. Short cycling the AC means you're not dehumidifying the air. Half the work of AC "should be" dehumidifying. You'll feel comfortable at a higher temp if the humidity is lower. The same holds true for heat except you want to introduce humidity. If you have a humidifier installed onto the heater but it short cycles, you're not benefitting from the humidifier as much as you could be. As you stated, you want your HVAC system to run 100% (all day) when the temps hit their extremes for your area. In the Philly area we used 0F for heat and 100F for cooling. If your HVAC is cycling on & off on the most extreme days, it means you're literally throwing money away the entire time it's running... All year. Thanks for bringing so much good info to people who crave it.
We replaced just the outside unit with a heat pump. I think the retail price of the unit was about $3-4k. Our HVAC installer charged us $9,000 and it took an understudy only 4 hours to complete. More attention is needed on the price gouging in the industry and the lack of willingness to provide fair pricing. That said, we saved a good $15k by not also upgrading the attic unit (blower). Replacing it would have necessitated 240V wiring and another breaker. We kept our gas furnace and have dual fuel with gas as the backup. We have a 3 ton unit for a 2,600 sqft modern home in California. Every calculator online seems to think I need a 4-5 ton unit, which to me is absurd. I don't think our heat ever ran more than 2-3 hours in a single day this winter.
You can't buy a furnace or a heat pump without going through a licensed HVAC dealer.. It's literally illegal in most states.. It's common in all of the building trades for the contractor to double their money on equipment and material sales.. Plus, charge for installation of the equipment and materials they sold you.. That's just the way it works.. If you don't like it, spend 4 years doing an apprenticeship, tens of thousands of dollars on tools and equipment.. Pass all of the test you have to take to get licensed.. Then spend 3 or 4 days crawling through your crawlspace and attic to do the install yourself.. I'm an HVAC technician.. There's a lot of overhead involved that we can't charge you for directly on the bill.. We don't make as much money as people think..
@@MarkLada My HVAC guy (owner of a 3-person company) lives in a million-dollar house and has a collection of classic cars. He does just fine with his profits.
@KiwiandPixeltheParakeets There's too much competition to over inflate bids like that.. You wouldn't stay in business long at all that way.. A couple of hundred dollars can be the difference between getting a job and not getting a job.. Especially if it's a municipal contract or commercial job.. We make a good, honest middle class living, but we have to work our tails off and sacrifice our bodies to make it.. I guarantee you most people wouldn't go in some of the places I have to go into on a daily basis.. Crawlspaces so tight you have to drag your face on the ground to crawl through them.. Attics so small that you have to lay across 2x4s and work on your side all day.. Just wait, if you think HVAC stuff is expensive now.. The government keeps imposing stricter and stricter regulations on us.. Equipment prices are going to more than double in the next few years..
@@MarkLada Maybe you don't make much as a technician, but your company owner is probably raking it in at your expense. Perhaps with all that training it may behoove you to go into business for yourself. Just a suggestion. None of what you said negates the fact that HVAC owners are absolutely raking it in with sky-high pricing.
I clicked on the link and got to the condensed version. Then you got me interested in the extended version, so I clicked on the link. Then you got me involved in the condensed version, so I clicked on the link.
I enjoyed this as well, and I can totally see why it is necessary. I like the rambly version more, but this is the one I'm going to send out to several friends who are looking at hvac upgrades in the near future.
@@TechnologyConnextras I agree that I find this more compact version more enjoyable, however I love the fact that you are offering both, mostly because for a topic that I care more about (like the pinball machine videos as I find it fascinating) I'll probably choose to tune into the longer format video
As someone who is a fan of the channel but doesn’t have any background knowledge in this field, I also like this video more because it’s a lot easier to follow.
1. Your heating/cooling system is sized for extremes, the coldest and hottest days of the year. So it will be "oversized" 360 days a year. Because if its not, the end user will complain. We wouldnt size them like that if we didnt need to. 2. Equipment goes by tonnage, a ton of cooling is 12,000 BTU per hour. Equipment models usually step up by 1/2 ton, sonetimes 1/4 ton a time. A house may only need an extra 500 btu an hour to meet the extremes, but the next possible size up may be 3k-6k more btus. 3. Modulating systems that can adjust capacity depending on need do exist, but they are more expensive. 4. If you want a "normal" size system, especially a heat pump, keep in mind that it may not keep up in extreme conditions, and you need to leave them on 24/7. If you turn the thermostat off at night or when youre at work, they will not be able to get back up to the desired temperature for hours.
My 1970's bungalow (*) in frozen capital of Hoth (Winnipeg) is heated with resistive electric forced air furnace. I've wired sensors everywhere. I can say with much certainty a single 5kW element will easily maintain my home at 20C through our coldest winters (to your point, it may not recover from a 3C overnight setback when it's -30C outside - but the temp won't drop). My 3x5Kw furnace rarely runs the 3rd element as it stages up (only when recovering on cold mornings ) (*) Walls are original 2x4 R12. Attic is R60 (thanks to recent utility rebates on insulation). Basement is R20 and windows are triple pane.
@@kw_boeing $225/ month. Switched when gas was all time high and hydro was less. Cost of high efficiency gas was more than double an electric. Switching from the original gas to electric did not increase my gas+ electricity bill. And I'm comfortable fixing an electric furnace in the middle of a cold winter night. Not comfortable touching a gas furnace with all its sensors and confusers.
The way that heat loss works, it will always be able to recover back to design temperature. It will take longer with less power, but it will get there.
The part of me that loves your stuff wants to listen to the full version but the part of me with things to do is happy for the condensed one. good job. now to fill the condenser with new refrigerant..
Actually came to watch the condensed version just now because happen to be in a situation where a friend could benefit from the information. So thanks again, not only for the original version but also for this more shareable version!
Great video! I thought I was the only one goofy enough to add up space heaters to verify how much heat pump capacity I needed! In addition to adding up space heaters, I also ran a Manual J calc for my house. Then I looked at the spec sheets for my heat pumps to make sure I'd have enough heat on my coldest nights. The mini-splits don't have backup resistive heating, but I do still have my science experiment space heaters in case I ever need them! You might have covered it in the longer video, but it's worth pointing out that heat pumps' output ratings are benchmarked around 35-40 degrees F. At 35 degrees F I have 34 kBTU/hr (about 3 tons) of heating. At -13F, I'd only have about 15 kBTU/hr (about 1.25 tons). In an extremely cold environment, that would be one reason to size the heat pump up.
@@DaveTapley In short (and simplified because I don't quite remember) he was worried about pipes freezing in a crawlspace, as the air ducts wouldn't provide heat anymore and the space heaters are overkill for such a small space. So he added 100Watts of Christmas lights to provide heat (and festive atmosphere) to those places.
We in Holland use a gasheater to warm central heating water. I adjusted the temperature from 80 degrees back to 55 and the total output in kW back to 25%. Saves tons of gas, only takes a little longer to warm up the house.
same here, the factory default of our boiler is 75°C for the heating and 60°C for the hot water in the shower, like who the hell wants that hot of a shower?!?
@@GameCyborgCh Hmm, my boiler has a pre-mixer, this allows me to heat the water in the boiler to 75C and get away with just a 300 L boiler running for two of the cheapest hours of the day and still get enough hot water for three teenagers and a wife. :)
Used to be, houses leaked a lot and were poorly insulated. The furnace had to overcome that or homeowners complained loudly. So massive oversizing was the norm. Nowadays, they are supposed to be well built, well insulated, and well sealed. But there are so many homes built to code minimum, that most arent correctly insulated, sealed, or even properly built. So they are still being oversized. Heat contractors arent being paid to perform a full house blower test and thermal imaging to see what it really needs. And then reccomend all the fixes be done as part of the install process. Take a thermal camera around your developement at night to see what it looks like. Then check older developments and single resident homes, apartment buildings, and even commercial buildings. (Old man grumble 1st thing in the am without coffee...)
100% with you. When I bought my (now 115 year old) home, it had a 100KBTU/hr oil burner feeding steam, which was, generously, 75% efficient. Originally, the house had a central coal burner. The house was not tight, the windows were original, loose, and several broken, threr was little insulation. First thing was add insulation where easy and plug the big holes. I had no problem the first winter with a 22KBTU/hr ventless gas unit and a 1500W electric to back it up (don't judge me on the ventless unit. The house STILL isn't very tight despite 15 years of work). When I did the main system, I ran a manual J, got 44KBTU/hr, not considering the added insulation and replacing the windows. I put in an 80KBTU/hr, 96% efficient condensing hot water unit with panel convectors to replace the steam sectionals that also does domestic hot water with a 30gal tank. External sensor sets the firing rate based on outdoor temperature. The inspector (lets call him "Bob") wanted to fail me because the ruie is a replacement must be at least as big as what is replaced. He couldn't show me the rule. I showed him the calculation and he said that Manual J is BS. Those guys that wrote it don't know what they are doing. But if I want to be cold and have pipes freeze, it's my problem, and signed the tag. Never a problem. I can hold 75F when it is -15F with 30Kt wind. For 22KBTU/hr. And be able to shower, wash dishes, and do laundry all at the same time. I can't het pump, though, as I have a 60A service (from the post-WW-II upgrade) and there is no capacity for anyone in the region to upgrade. Don't get me started on the local utility....
My new house got installed with a heat pump per my request thanks to your videos so thanks Alec! Having that unit also saved me a lot of space in my garage which is a huge bonus for me since I actually use my garage to store my car. I move in to my new home in about a month and I can’t wait to get all nerdy with my guests about my ac unit that I’m weirdly proud of.
The reason why summer AC needs the same amount of power for a smaller temperatzre delta is humidity or more accurate the dehumidification that happens during cooling. As you covered there's A LOT of energy in the latent heat of vaporization and the same goes for the condensing part and that water from the evaporator doesn't go through another heat exchanger. In 99.9% of the cases that cold water will be dumped straight out of the house.
I used to live in a middle apartment with people above, below, and on 2 of 4 sides of me. Only 1 small and one long outside wall. I NEVER turned on the heat, even in the dead of winter and the temperature was fine. Didn't save me any money, though, because the whole building's electric bill was split evenly. 😂 Now I have an approx 1400 sq ft detached house, built in the early '80s, and our 24k BTU heat pump seems to work very well except for those few days in the dead of winter when it is really REALLY cold. And on those days my heated blanket is a great friend. ☺️
Hey bud, we have the same issue over here in the UK. My house which is less than 5 years old came with a gas boiler (furnace to you guys) and we didn't get the option for a heat pump even though we bought the house before it was built. That aside, I have reduced my boilers temperature (actually on the boiler) down to 38°c which is more than enough to heat the entire house with radiators to 21°c. The manufacturers recommend 60°c which is crazy as it is a condensing boiler that reclaims lost heat from the condensation created when it's on. The lower the temperature, the more condensation, the more heat is reclaimed, the less gas and the more economic it is to run.
A boiler is a boiler here as well. A furnace, in our parlance, doesn't boil anything. It typically heats air with natural gas burners through a heat exchanger, and then that heated air gets forced through air ducts to the entire house. Unless you call such a system a "boiler," which would be wildly inaccurate in any country.
@joesterling4299 oooh, I never knew that. I actually thought that gas boilers and furnaces were the same thing except in the US they heated the air because you all use air-conditioning too, and it just made more sense than installing radiators and ducting for air-conditioning as well. We simply don't have furnaces (at least not in houses) over here.
@somethingfunny6867 I have set a "fall back" temperature on the thermostats to 16°c although it's never dropped that cold. Even if I finish work early and check the temperature, it's no lower than 17.5. I'm guessing my house is well insulated. There's a channel called heat geeks. They mainly focus on heat pumps these days, but older videos focus on gas boilers and setting it up correctly. I was thinking of buying weather compensation, but before investing in getting it installed, I tried lowering the boilers temperature (which is what weather compensation does depending on the outside temperature) and found that 38°c seems ideal. It will be slower to get to 21°c than having the boiler set to 60°c or more, but it also heats up more slowly, putting less strain on the system, and it doesn't over shoot the target temperature.
You can get more geeky by adjusting the flow rate to each radiator, but that is something I give up as a bad job. I have all my radiators fully open, and although you think I will be heating rooms I don't use wasting energy, the heat from all the radiators goes into heating the entire house. If you turn off a radiator to 1 room, the other radiators actually need to work harder to heat the rest of the house up as the heat will transfer into the colder room. It's all about energy states and equilibrium. You might as well have all radiators and rooms at the same temperature since it gives you more internal thermal mass to keep the house warmer for longer.
I appreciate the shorter version! Sometimes I am deeply fascinated by a topic of yours but can’t quite commit to the beefy ones. I am LOCKED IN for this one
As a Brit, I remember growing up in the sixties and seventies with gas being charged in british thermal units (BTUs to you) but even then, electricity bills showed kWH. I studied physics to A level, using text books dating from the 50s, but never heard "ton" used as a heat unit, until the mid 80s when I shared a university flat with some American exchange students who were studying engineering
Excellent video! As a homeowner than may need to replace my gas furnace soon, all this is good the know. I had an early model Rheem heat pump back in the late 70s, to augment my gas furnace, and unfortunately it was inadequate to heat my home below 35°F-40° F and I replaced it with a 3 ton A/C unit. Good to see the technology has gotten much better. Having a large 3 acre lot, I may also explore a geothermal system.
@dennissmith8199 - it is normal for conventional heatpumps to not be able to give enough heat much below freezing, those units are still very useful in shoulder seasons and worth getting instead of an a/c when doing equipment replacements. they are still made. there are plenty of mild days during the heating season. Cold climate heatpumps are loaded with electronics, that is the down side. this being said, a 70s heatpump would have been like 5 hspf and not worth running compared to gas, new ones start at about 8 hspf efficiency.
funny thing, not really related to the content of the video. I saw the notification for this video on my phone and saw the words, "condensed version" but when I got on my computer and logged into youtube, it recommended the full version. thinking I was watching the condensed version, I was.... a tad worried that the condensed version was an hour long. So thank you for linking to the condensed one in your full length video.
I'll be honest, I live in a trailer with no central HVAC system and as far as I'm concerned, my housemates horribly overuse space heaters. I live in a climate where we're lucky to get one snow a year and even when it snows, it's usually slush. We didn't even get slush this winter and had 70+ degree days in February and the coldest nights barely got into the 20s. Aside from avoiding chills getting out of the shower(which high air temperature doesn't really accomplish anyways since we only have like a 15 gallon water heater that's inadequate for bathing), the only time I'd bother with the space heaters if it was up to me was keeping the pipes from freezing on the rare night it freezes(And honestly, it's a bit of a head scratcher for me that modern plumbing isn't designed to account for the expansion of water as it freezes. The rest of the time, I'd rather just bundle up in my favorite hoodie it's too hot to wear most of the year or cocooning myself in blankets and let my metabolism keep me warm. Sadly, this tin can also heats up to over 100 in the summer and most of the windows are too small for a proper window AC and where I live is too freaking humid for evaporative cooling to work, so I had to fork out for a portable AC... and linking back to the subject of the video, the smallest, cheapest one I could find is advertised for a room two to three times the size of the room it's in.
One other way you can test if your house is ready for a heat pump, provided that you’re able to change the temperature of the heating medium (water through radiators or air through ducts): lower the temperature and for shits and giggles see how low you can go while maintaining comfort. I’ve been able to lower mine from the default 70 Celsius down to 45 Celsius. And now that I have underfloor heating I managed to make do with 35 C.
This is a good test for hot water systems (and also increases boiler efficiency) but it doesn't work for forced air furnaces. Furnaces output a fixed amount of heat regardless of the output temperature.
14:00 other method : during an off we, read your meter when you leave, and come back, let your heater at 20C, and time how long you were away. The test must include at least one night, possibly 2. Check the average external temp over the period. Now you can calculate, for a given delta temp ( internal - external ), the energy used over a given time . That gives you the thermal resistance of your house. Your fridge was working ... But was contributing to heating so does not matter.
A sizing rule of thumb an ASHRAE old-timer told me was used long ago... Stand at the curb in front of the house. Hold your had up, fingers up, "stop" style. See how many fingers covers the width of the house. that number is the tons of heating needed.
In FL I've only ever had a heat pump. I don't know it any other way. I remember heat pump advertisements back in Missouri all the way back in the 80's, though. Had no idea they were considered new or exotic.
I'm a Hvac mans and leaning the Manual J and Manual S right now and have been in the industry for only four years. I have never been told to not tell a customer what a heat pump is or how they work. This is not a secret. They are great systems. Sounds like it's just bad companies or a bad sales man that actually picks the equipment to be installed. A good sales man will inspect the duct system when sizing equipment. Nothing should be assumed that anything is okay and we (me at least) were taught this in the Manual J class. Not every Tech knows how to do these calculations and its not their fault; it is the companies fault for not providing a qualified person to take the time and effort to do it in the first place. A lot of companies just tell their Techs to (just make it work or just sell this or that rather than fixing the root problem). You need to find a good company and do some research as they are out there. In south FL, most homes down here have undersized duck work. Why? No idea but we all know about it and yes it causes problems to the whole system. But it is slowly getting fixed with new construction. It is very expensive to replace an existing duct system and the vast majority of people cant afford it. Duct sizing is just as important as finding the right tonnage of a AC system. A senior tech once told me "AC is going to become a commodity for the rich" and I truly believe that.
I am a mechanical engineer that sometimes dabbles in HVAC. I am not in any way going to argue that the HVAC industry is "good" or that heat pumps are not worth the investment. However, I am going to argue that oversizing a gas heat furnace is not as detrimental as is being argued in this video. Yes, an oversized furnace DOES produce more heat than is required, but for less time. it will still produce the same BTU/hr on average that a furnace sized exactly right will produce. This was demonstrated by his thermostat calling for heat only a portion of the time but maintaining a near constant indoor temperature, even though his furnace can produce 4x the heat required to maintain the indoor air temperature. Yes, if you had an 80,000 BTU/hr furnace that was running constantly, that would be bad as your house would quickly heat beyond what most of us would consider livable. But on those wicked cold days, the 80,000 BTU/hr furnace is only running 25% of the time, producing 20,000 BTU/hr average heat output. I deal mostly in industrial applications, so I can't speak to residential equipment costs. But in my experience, keeping all other factors the same - primarily the amount of air volume the unit can handle - the cost of the unit does not change much by just changing the heat capacity. Meaning, you're not loosing more than a few hundred dollars by going with a much larger furnace than is strictly required. The reason that this matters is that even though air is a relatively light substance - compared to water or bricks - it still takes energy to move. If your furnace is moving air around your house 100% of the time, the blower motor in your furnace is going to be drawing power for that entire time. If you are only moving air around your house 25% of the time (when the furnace is running and producing heat), your power bill will be less. It will also reduce wear and tear on your equipment (bearings, belts, motors, etc.) which increases the useful life of the equipment. If your furnace is producing too much heat all the time, no one would argue that its a good thing. Our furnaces should be producing only as much heat as is required. But if your furnace is capable of turning on and off more than once a day, producing more heat than your structure is loosing to the cold outside does not pose any problems. The furnace simply turns off when not needed, reducing the amount of power required to move all that air around your house.
I learned so much when replacing my heat and AC units. We have an efficiently sized unit for a 3600 sq foot house and when first installed seems too “weak” for the house when you’re used to typical air blasting from the vents. My dads furnace is so oversized that when the heat turns on, loose papers will fly off the coffee table Efficiently sized units should run longer with fewer total on/off cycles - especially when running the AC as it provides not only cooling but dehumidification
The difference between the tonnage required in heating vs cooling mode and the outdoor ambient temperature is because temperature isn't the only heat load in your house. The people in it put off heat, your appliances put off heat, your electronics put off heat, and most of all there are direct and indirect solar loads that hit your house on a daily basis. This means you actually get a helping hand in cold weather but a lot more energy to reject in hot weather.
In my townhouse there's a boiler for heat and hot water, a heat exchanger in air handler to transfer that heat to the forced air system, and an AC unit. It would be straightforward to simply replace the current AC unit with a heat pump (and that's my plan). With the boiler still online there's no downside to having the heat-pump a bit on the small side. Further, in my particular system the evaporator/condenser is before the heat exchanger. This means that you could conceivably run heat from both a heat pump and the boiler simultaneously, allowing the boiler to be down-sized as well. My system here in Toronto was more reasonably sized than yours with the heat exchanger rated to 40k BTU and a 1.5 ton AC unit.
I just went on the carriers website and they make the following statement. “Typical residential gas furnaces will be available in various sizes between 44,000 BTU/h and up to 120,000 BTU/h.” It’s possible that the high-efficiency furnaces may not come in sizes smaller than 60,000 BTUs. So you may have gotten the smallest furnace that you can get. It might be a good idea to talk to someone in the furnace manufacturing business to find out there take on this.
Good points. My 1200 sq.ft. house, in northern CA. had a 100,000 BTU/hr. furnace installed back in the '70s. I made a video about that furnace a few years back titled: "Getting the Old Fraser Johnston Gas Furnace Running" On-line calculators estimate a 36,000 BTU/hr. rating would be sufficient. I suspect even 20,000 BTU/hr. or a 2 ton heat pump would be more than adequate. I don't use the furnace, instead heating the house with solar hot air with backup from a fireplace insert.
Snow! I feel snow does not get the attention it deserves. It only takes minutes to clog an air sucking heat pump up and it takes perhaps 15 minutes defrosting itself. It will lose that battle. The solution seems simple: put a little awning over the unit.
There's an HVAC guy in Lansing Michigan (All Star Mechanical) who has had a couple rants about this. Apparently his small company is the largest installer of 40,000 BTU furnaces (the smallest Trane makes) in Michigan. Trane sold 83 40k units in Michigan last year, this guys small shop bought 37 of them. In the last year Trane sold 390 80k BTU furnaces. This guy bought one of them.
I keep my thermostat set to 15 C (~60 F) and use a portable heat pump just to heat my office during the day. The usual inefficiencies of portable systems barely matter when moving heat within a closed system, and heat pumps are most efficient across small temperature gradients, so it’s 2x super effective. It’s basically using the same principle as multi-apartment systems discussed in the follow up video. Technically my heater needs to work a bit harder to stay above 15 than if I was on vacation, but during the day just passive heat usually will get it close, and by now (March) it reads 16-17 before I even touch the thermostat in the morning.
Years ago, I bought one of the first high efficiency furnaces. They only made on size (75000 BTUs) which was way too big for my house. The installer said they would put in a restrictor plate to bring the furnace down to 35000 BTU. You might want to check and see if they make a restrictor plate for your furnace to bring it down to 20000-25000 range.
I work with heat pumps for Massachusetts' energy efficiency program and I wanted to reply to something you pointed out, using existing ductwork for heat pump systems. It is very rare that old houses (i live in the north east, so most of our houses) have ductwork that be utilized by a central heat pump. According to the policies our company uses, each floor needs to have a return duct (which disqualifies most 2 story houses) and the ductwork often just isnt large enough even if they do have a return duct. I dont need to know the heating load to run this calculation. Any home we can't fit central heat pumps in we pivot to ductless mini splits. As far as sizing heat pumps, it is slightly more complicated than you portray but you are almost right on the money for the sizing range. The thing to keep in mind for DMS is that the snallest head you can get is usually 7,000 BTUs, and the most heads you can get on a compressor is usually 4. This means you often end up oversizing the head in one room to cover the heating load of an adjacent room which is too small, and often means oversizing more than just the sum of those two rooms to make sure the heat properly spreads, especially in older homes which trend to having more but smaller rooms with less continuous airflow between them. The other thing to keep in mind is that heatpumps really shine when they are holding a home at a continuous temperature, meaning that the more insulated your home the more you will benefit from heat pumps rather than a one stage system. Almost every state has an energy efficiency program offering MASSIVE subsidies for insulation work, my state targets a 1 year ROI on any money put into insualting a home, so if youre asked to oay $2k for the insulation work thats also likely what they expect you will save that year. Everybody should be having these assessments done, they are free in most states.
I would really appreciate you used the same units for thermal power. You've been alternating between BTU/h to W to Tons as if everyone knew the conversion factors. I'd say you stick the audio to one unit only and put the converted units on the screen for whoever cares.
Speaking as a (now retired) 38 year engineer - electrical rather than HVAC but the idea is the same. The principle often used is: if you oversize there might be some grumbling about price. If you undersize, lawyers get involved and that is a bad thing for the supplier and designer. Your point is very valid, we should design closer to actual requirements, there just is a tremendous aversion to being sued.
In my previous home, we had a 40kW heater running on diesel. We replaced it with an 8kW pellet burner. Saved us lots of money, was much more quiet and easier to run. And we were never cold. If we'd have to do the same today, we would have gone for a heat pump in stead of course.
I was worried about being up sold when buying a furnace but was reassured that there's minimal price difference. It's mainly just the gas orifices that differ between similar sizes, which makes it even more strange that this is such an issue. I found a company that said my old 80k btu was oversized and recommended 60k btu. It sounds like AC/heat pumps are a different story though. One option with an oversized 2 stage furnace, either because a heat pump has been added or just in general: Connect single stage thermostat wiring to just the 1st stage/low heat of the furnace and set the furnace to 2 stage/manual mode so that only low heat is used. Only if it's adequate of course which could be calculated based on furnace specs and would result in more even heating instead of the furnace's auto mode going to stage 2 unnecessarily. Could be useful for older thermostats but may not be as much of an issue with some smart thermostats. Mine tends to use stage 2 too quickly but I may try fiddling with the smart thermostat settings instead because stage 2 is nice for quick heat recovery when needed.
We had two contractors quote for installing heat pumps this year, to take advantage of a government grant. As is usual in the U.K. we have a condensing gas combi boiler which provides hot water for both hot taps and radiators, so we were quoted for an air-water heat pump systems. Since our existing radiators were sized for high temperature water flow from a gas boiler, every one would have had to be replaced with a larger radiator to cope with the lower temperature output of a heat pump. Replacing every radiator with and even bigger one would require a lot of work, so even after the grant is taken off the price, the total wasn't much less than just having a Ductless mini-split air conditioner installed in every room, and these would give us cooling in the summer as well as heating in the winter. So, we decided that it makes more sense to keep our Gas central heating for hot water, and backup heating, and invest in air conditioners for the bulk of our heating and cooling needs. We wont get the rebate, but we get a lot more functionality for a lot less hassle and not much more money. Oh, and it's worth mentioning, before anyone tries to fit an AC unit themselves, you should definitely check your local regulations. In the UK, you need F-Gas certification to do any work on A/C or heat pump systems.
Also in Chicago (Oak Park). Just put in a solar energy system and looking to completely get rid of gas. This really made me feel better about replacing our 20 year old oversized furnace with a heat pump like I have been planning!
A oversized gas furnace can have its primary heat exchanger crack from its short cycling like mine did. I went from a 75,000 btu furnace to a 45,000 btu model which is more inline for my sometimes very cold NW Wisconsin home. I’ve seen it get down to -38f a few times up here.
if you want to cut down on the capacity of the furnace, just plug the outer burners on the furnace. all you have to do is pull the burners out and take out the orifices on the manifold( screwed in/ pipe thread) and install plugs ,and reinstall the burners. we did that on furnaces that had bad heat exchangers, so the customer could at least operate the furnace until the weather got warmer, and give time to get a replacement furnace ordered, and installed. the outer burners being shut down will not cause problems with the hot surface igniter, flame sensor or the flame runner. .the regulator in the gas valve will automatically adjust the gas pressure to the manifold. you got a furnace that is the smallest unit made, and is still too big, all I can say is "OH WELL "at least it is not the other way around where it is under rated.!!!! I would not remove the furnace, as it would make for a nice back up heating system( second stage), incase the heat pump would fall on its face
Oversized everything is a big problem, Alec! Thanks for focusing on the HVAC! Over sizing of heating equipment is rampant My only issue with heat pumps is an issue with forced air heating in general: it never addresses radiant heat and mean radiant temperatures of exterior walls. For one particular cool spot I use a mere 100w ceramic brooder lamp and the comfort level vastly improves with little change in air temperature. But that’s a subject for another day
There's a practical factor involved in using either resistance or gas heat strictly for peak-day supplement. That imposes a huge (system-wide) demand spike on the generating system and distribution grid that causes peaking generators to come on, running at the highest cost per MWh. That cost isn't recovered in the few hours of energy sales at "normal" kWh rates. Utilities, in their own defense, could then decide to add a 12-month ratcheted demand charge (as they generally do for commercial and industrial customers). After all, the entire grid has to be sized for that design-day peak load.
A couple of factors you are forgetting. 1. If your neighbors house is warmer than yours, you will be stealing heat through the walls. So if you have an elderly neighbor that likes the heat cranked your going to need less btu's to heat your place but if one moves in that likes it colder they will be stealing btu's from your unit. 2. Most places are designed that you can move a couple of degrees aka gain heat which is more than btu's needed than to just maintain temp. This is done for power outages or because people keep their house much colder when they are not home.
I've been surprised before by how little HVAC capacity a well-insulated living space actually needs. My current apartment is about 700 square feet and in an older building, but one that was modernized with (at the very least) energy efficient doors and windows. I don't know the actual heating and cooling capacity of the HVAC, but when I moved in, I noticed that the condenser was tiny, possibly the same size as the condenser on an extra large window unit. I'm used to big barrel condensers, even for similarly sized apartments, and was worried it wouldn't be able to cool the apartment adequately, but this past summer it worked just fine.
I use a heat pump (in Florida) and its so nice. I also have an HVAC guy thats honest and downsized my unit (saved me a few Gs) and it cools and heats my house just the same as the old unit but also uses about $30 less of electricity in the hot months.
I had that problem. when my AC came on this huge blast came with dramatic loud noise. I had a friend over who used to do this kind of engineering before he retired. He looked up at my vent when it came on and said "your AC unit is too big." Yeah, we were sold more expense than we needed. I live in the South, so we RARELY need the heating coils.
I just went through this to take advantage of the recent Canadian rebates for heatpump installs. I had a ~75,000 BTU furnace and a 3 ton AC. It was replaced with a 60,000BTU gas furnace and a 2ton heat-pump. It's all setup so the smart thermostat uses the furnace when the outside temp is below a threshold and the interior temperature difference is too big and otherwise, the heatpump operates. By comparison, my house is two stories + basement and about 1600sqft. Now the issue we have is that the smart thermostat wants to inform me when the furnace runs for too long.
11:08 Missed opportunity to say miles instead of kWh when describing the total kWh consumption of heating your home in the test. Obviously this is a real strech of units, but I'm people say "we dont have enough capacity for everyone to have electric cars" but easily have 110kWh to heat with resistive heat. Thats enough juice to drive 3-400 miles. Great video as always!
We have a 28kW combi boiler which is way oversized for heating. From what I can tell, on the coldest days we have, I use about 120kWh gas. Optimistically at 80% efficiency, that's 96kWh heat, or 4kW running continuously. Replacing that with a 5kW heat pump and hot water tank soon hopefully
This is fantastic, Alec. Preach! When we were sizing for a geothermal heat pump here in Central Illinois there was definitely a push to oversize for a home that has (insulated concrete foam) walls rated at R-25 running to the roof. Even with drilling wells, that entire system was WAY less than the $20k wacko quote you cited. Do you have recommendations for smart thermostats which are NOT tied into a big data company like Google? We want to track that data inside our own network, and don't want to be reliant on a third party that probably has a privacy policy worthy of one of your loving 30-minute shame fests.
Ecobee can be local, in my understanding. But there are many options. Key words for internet searches would be things like "local only control". I recommend engaging with the Home Assistant community as well; zero-cloud smart homes are a big focus for most of us.
I had to get 22 estimates to replace my oil furnace with a heat pump because all but two of the estimates were predatory, in exactly the way you describe. They tried to sell me heat pumps that were 3x bigger than I needed PLUS a gas furnance to supplement it! Estimates were: 1 @ $12,000, 1 @ $15,000, 17 @ $22,000-28,000, and 1 @ $42,000 (this snake said my house needed 2 6-ton heat pumps). Also, the heat pump I got ($12,00 estimate) is waaaay more energy efficient than the ones quoted to me that were 3x the size I need. And, just like you say, the oversize units would have required me to replace my electric panel. Just like you describe, my central duct system doesn't have the capacity to handle the giant heat pumps they were trying to sell me, but its the right capacity for the appropriately sized system I bought. I thought I was going crazy when I was getting all of these estimates, so I called the state Department of Environmental Quality to ask what capacity heat pump I needed for my home and they confirmed these $20k+ estimates were insane. They were totally clueless that companies are giving estimates like this. I also used the J Manual calculator and it confirmed the size heat pump I need. When I said no to these wild estimates, and expressed disappointment that the units they were trying to sell me had such low energy efficiency ratings, then they tried to sell me ductless mini splits, even though I have a central duct system and mini splits would do violence to the architecture of my 1890 Craftsman home. I also have a bee in my bonnet that they all told me I had to have heat strips. I looked into heat strips. They are the energy equivalent of using space heaters in every single room in my house, which is wildly energy ineffecient. I said no to heat strips and on the 0-2 days a year the weather is much colder than normal for my climate, I use a space heater in each of the 2-3 rooms we actually use at the same time.
In Europe the "combi boiler" is a common thing for hydraulic heating and warm tap water. The tap water means that these are severely over specified. But, they do allow power control over a good range, for example 6 to 24 kW. How low the low end is gets more attention in recent years. I've capped mine to its minimum setting.
As we turn to secondary heat sources and heat pumps, contractors will feel less need to overshoot the requirements as they did with typical gas furnaces. You design for what you currently have available, not for what MAY come in the future. People don't want to freeze their butts off now just because they MAY be able to afford an upgrade later. But you are correct in that most contractors rarely do their manual J beyond the initial install.
I used to work with people who sold heating and plumbing units. The manager would just ask "Whats the square footage, what's in there now, how many floors", do four lines of napkin math, and point them at a unit. They only ever downsized if the customer stressed "It's *brand new* construction."
It barely got under 32*f here a few times this winter. My Gas Furnace is from 1975, I'm scared to run it, its a 80,000 BTU unit for a 1400SF house... it heats me fast. But power is cheap for me (9c/kwh at night) so I plugged in a space heater, set it on level 1 (600W) in october. I am here in november, and my main gas heater has only clicked on a few times all winter. IMHO amazed a single space heater kept me warm all winter.
Are you looking for a more cantankerous version of this video where I go over more of the experimental design, with 138% more runtime and 75% more snark? Then the main channel video's got you covered!
th-cam.com/video/DTsQjiPlksA/w-d-xo.html
@@linuxgeex Nah. For one, you're missing that the design conditions only showed up for ~36 hours total this year. And when we're talking about heat pumps, where the compressor only gets lubrication when it's running, shorter cycles are actually _bad_ for them. Short-cycling kills equipment, and that's what my furnace is doing all the time. It's less bad for the furnace, to be sure, but it's absolute hell on a compressor.
And as I said - you need to get comfortable with there being secondary heat sources. That provides the margin.
Any chance you might be able to do an HVAC video on apartment heating and cooling? I.E. more specifically HVAC where you're not allowed to make any physical changes to walls or ducting, and or perhaps options for heat pump style window heating/cooling systems.
I know you did a video on portable air conditioners and your hate for them, but perhaps more on figuring out what kind of output you need based on the size of the apartment, and perhaps on window units that actually function as a heat pump since there are a few that do.
The efficiency of smaller heatpumps are higher reaching a COP of 5 at the rated output than larger ones are going to be closer too 3 or 4 at best. The reason for this is that not everything is suitably upsized and therefore the efficiency suffers. But what is the COP when not running hard out??? Turn out if running lightly while these numbers are never published a larger heatpump running on low power can have a COP well above 5! And so the more hard out a heat-pump has to run the more you pay for the same heating (or cooling).
You live in a town home? You haven't accounted for the fact that you may be getting residual heat from your neighbors
The ol switcheroo
I am very impressed how Alec didn't just chop pieces of the video out, but wrote and produced a seemingly almost completely separate script and filming session.
I was initially just going to put this on with the volume down to give him the algorithm boost of engagement and watch time, but then I realized that it does, indeed, appear to be a whole new (if _very_ similar) video!
A video literally scripted for our friends and family, not just abridged for them. wow.
As I just discovered by hearing the start of the full video while looking for the link, even the first line is re-recorded
It's definitely got a fair amount of re-used footage, but more than enough new stuff to tie it all together.
I’m so glad you made this condensed version, I love the big main video but it would be overwhelming to my mom who plans to get an AC unit to replace her swamp cooler and I’ve been trying to talk her into getting a heat pump
Yeah this mid-length is great for sharing... and putting it on a different channel is the right move. I really wish TH-cam would allow channels to publish multiple sub-channels so we could separately subscribe to topics and formats... for the most part I would use it to avoid the Shorts... like Integza putting out 3 related "I did a " Shorts a year or more after the video they reference. Ugh! So yeah, this channel is awesome, and if you do Shorts, please make them a 3rd channel.
I went here for a shorter version, yet the "short" version is still 26 minutes!
@@RomanShein1978 I immediately switched here when he pointed out the length of the main video, and even 26 minutes is longer than I normally prefer for single-topic videos. But his content is always worth the time.
Good luck, I thought I had convinced my parents on installing heat pumps for their home remodel, but they balked once they got quotes from some HVAC contractors.
It's a huge missed opportunity in futureproofing, as we live in the Bay Area where we don't need much heating capacity and where some cities have started phasing out gas appliances.
@@joesterling4299 I like his video too. I only complain about his definition of "short". IMO "short" should be more like 10-15min.
I just went through this in the last two years. I had a ~75,000 BTU furnace and a 4 ton AC. It was time to replace and everyone wanted to replace with same same or go bigger. I finally found an HVAC contractor that did the calculations and showed his homework to prove it. Taking into account all my home upgrades, he calculated that I only needed a 40,000 BTU and a 2 ton AC. I was very skeptical but the math doesn't lie.
This saved me a bunch of money and I was able to change my 40 AMP breaker for AC to a 20 AMP. It continues to save me money on my electric bill. You are right, on the coldest and hottest days it runs just about constantly. BUT IT IS DESIGNED THAT WAY. And those extremes are only a very few days a year.
Make your HVAC contractor do the Manual J and make them show you their homework. Most will just walk away because they don't want to do the work. Those are contractors you don't want working for you anyway.
A smaller unit shouldn’t save (much) money on your electric bill; it still has to do the same amount of work, just spread over a longer period.
(Yes, there are some losses due to a larger unit short cycling, but they shouldn’t be significant.)
ITS DESIGNED TO RUN ALL DAY LONG AND NEVER REACH SET POINT 😂😂😂😂😂😂😂. fucking gold
@@k5sss assuming a single-speed compressor rather than 2-stage or variable speed compressor, and assuming the same runtime (work-hours) smaller unit draws far less current when it's running than the larger unit. a larger unit with variable speed should be comparable to the single-speed smaller unit in this example though right?
@@Robin-xe4yzIf the larger unit is drawing more power, then it’s running for proportionately less time, so the total work done is (about) the same.
Multi-stage and variable-speed units are designed to act like a smaller unit when that’s all that’s needed. That prevents short cycling but doesn’t change the total work being done.
@@bigxbudxbuddajust got the best salesman 😂
There was a *125,000* BTU/hr gas furnace installed in my ~1800 sq ft house when I bought it. It was replaced with a 70,000 BTU/hr two stage furnace that almost never runs on the second stage. The only time stage 2 was necessary was the day after you mentioned in 2022 when we got the same cold blast in Ohio. Even then it didn’t run full blast for more than a couple hours. Yep, my system was also oversized by 3-4x!
Our ~1900 sq ft house currently has a 115,000 BTU/hr gas furnace. The longest it has ever run in the winter during a single 24hr period was for 9hrs when the outdoor temp averaged 8 degrees Fahrenheit. Definitely overkill.
My apartment's maintenance guy is overworked and busy as hell, but thankfully he's an ABSOLUTE DORK about stuff like this. Just did this for our water heaters (i hear he vetoed the company's idea for on-demand heaters,) AND solved the moisture problem in our basements by putting condensers on them. The world needs more folks like him.
You having any hot water issues or weird symptoms? Our basement was way more humid when our venting seemed to be working the worst and it was hard to recognize it was from lack of air and/or some vent restriction. When symptoms were worst for us, it was way more humid than normal in the basement room w/ it and the only time winter humidity was a problem for us. The combustion exhaust apparently has quite a lot of water, even for the low output of a 36k BTU water heater, and it made a huge difference when I'm pretty positive it wasn't venting properly if at all. When it worked normally, there wasn't any real humidity introduced and there shouldn't be
@@Demoralized88 We're all electric with no central heating or anything, so I'm not sure our stuff applies to your situation. Also, I'd have to ask Dave, I don't know much about troubleshooting anything that doesn't have an operating system 🤣
One note of caution on kill-a-watt style energy monitors... they usually aren't designed to actually be able to handle high wattages for hours at a time. They tend to overheat and start melting the plastic casing. The problem isn't the shunt, instead it is the typically low-grade plug receptacle.
I had this happen to one of mine while I was monitoring a mere 700W of power for 4-5 hours a day. After about a month I took it out and realized that the plug was somewhat stuck in the receptacle and the plastic looked a bit melted and brown on the unit. It hadn't caught fire but the plastic obviously over-heated.
I ripped the sucker apart so I could get a good look, and It turned out to be oxidation of the contacts in the plug receptacle combined with relatively flimsy contacts. The area the unit has been installed in was clean, but the low quality of the device meant the manufacturer had cut corners.
I no longer use my kill-a-watts to measure high amounts of power unattended.
-Matt
That's where you need something like colorock's wired-in zigbee model. It's rated for 30 amps and actually built with a 40 amp relay.
@@superslash7254that's great to know about. The other option is something like Emporia, installed in the main panel with multiple non-contact sensors (CTs) to monitor multiple circuits.
Poniie PN2000 doesn't have these issues. It's also able to do 240volt
Most people aren't going to understand this, but for a Midwesterner, that Google rant was _pure unmitigated rage._ I'm surprised his hair didn't catch fire or something.
Wait is that a Midwest thing?
I so heavily just *felt* that frustration but I thought that was an everyone thing?
Please enlighten me I'd love to know about this.
The thing you learn by watching the Home Performance channel on TH-cam is that heating and cooling is only one dimension of the problem, and that taking care of the humidity is a second dimension that many people don't know about, much less do anything to address. And humidity can lead to huge problems in many areas, including mold and mildew growth, which can be a huge health problem. I'm glad you touch on it in this video, and doing a Manual J calculation, but I'd like to see you talk more about how important it is to control humidity.
I can one up you on this one big time. I just bought a home in Sonoma County (about an hour north of SF in California). Even being a 1940's home with no attic or crawl space insulation, Manual J calls for about 32,000BTU of heating need. Drops well below 2 tons once the crawl space is addressed, and down to about 1.5 tons when the attic is sorted. Someone actually installed an 84,000BTU furnace on this house... it was so oversized that there is evidence that it caught itself on fire at one point. There was a 90 degree temperature delta (Furnace was blowing 155 degree air when inside temps were 65 inside the house). The only reason I noticed it was so bad was I switched out my battery powered thermostat for an Ecobee which takes its power from the C wire. The furnace was tripping its own overheat sensor every 20 minutes and shutting down the thermostat.
People really need to know more about the basics of HVAC, what Manual J is, and the benefits of heat pumps. People also need to know enough to ask questions of their HVAC professionals, there are a lot of very smart, very good people out there doing good work... there are also a lot of folks who measure with their thumbs and are more interested in being done in a single day and never having to come back rather than doing a good job...
I have the same issue, our house is 1200 sq ft. and the last owner had an HVAC professional install a 60,000 BTU furnace for this small house, completely overkill. I installed an ecobee and the same thing happened to me, it would restart everytime the heat turned on it felt like. I had an HVAC tech out to take a look and they advised me that the furnace is WAY too large for the house and that eventually my heat exchanger will crack and fail due to the system overheating constantly. I'm in Ontario Canada, but even here it feels like the winters are getting milder and milder. So now I need to shell out for a new smaller furnace or just bite the bullet and install an appropriately sized heat pump instead.
@@Airseas TL;DR find a professional who understands heat pumps/Manual J load calculations and ask them about retrofitting your system for dual fuel and setting your furnace changeover point to a very low temperature (a really good tech will be able to recommend that temperature based on your region and gas vs. electric energy costs).
The long story:
Check out the rest of his HVAC videos. All the info is really great. You don't need to replace your furnace, you can get an appropriately sized heat pump (outside unit) and put an A-coil on your furnace and just use the furnace as an air handler. Gree makes a pretty affordable inverter heat pump that can be field installed as 2 or 3 tons that is designed to work with mismatched air handlers (it uses the temperature of the refrigerant as it comes back to the outside unit to vary how much output its sending). It's still not "cheap" and if you have a good/newish Air Conditioner then you are still stuck replacing something expensive... but if you happen to have an old AC ready to be replaced then this is a pretty cost effective way to adapt your oversized furnace to a much more efficient heat pump system. It'll never be as efficient as a fully matched heat pump/air handler/thermostat from like Mitsubishi or Fujitsu... but considering how much less it would cost to install, I think you'd still come out ahead until it's time to really put in a new system in 15-30 years.
The unit I referenced is the Gree Flex (aka GE Connect aka Mr. Cool Universal). My house has a GE Connect using the 17 year old furnace as a vestige air handler (we had the gas line turned off). We never get below 25 degrees outside, so ymmv but it never runs more than 1 hour a day here so even IT is oversized for us.
Not only was your furnace oversized, but apparently the duct work was way undersized for that furnace as well. Probably noisy too. A 90 degree delta for a scorched air system is about as unprofessional as it gets.
@@jamesnasium7036 yeah it was pretty bad. Luckily the previous owners had installed a heat pump as an air conditioner only. Got someone to come rewire it for heating and cooling and we are using that ridiculous furnace as an air handler. It’s not perfect but it’s safe and works a hell of a lot better.
I had to basically beg my HVAC installer to put in an undersized furnace when we upgraded from gas furnace+AC to gas furnace+heat pump.
"Don't worry, in winter, the top floor stays plenty hot from heat rising, we'll shut off the vents to the top floor in Winter; likewise the basement stays way too cool in the summer, we'll shut it off. It'll only be heating/cooling 2/3 of the total volume of the house at any time."
He finally agreed. And then we got a free upgrade (not in capacity, but in capability) because Lennox became so backordered they couldn't deliver the smaller-capacity, medium-capability one we wanted. So instead of a 2-phase, we got an "variable phase" (aka: it can produce exactly the heat/cooling level needed, instead of "FULL BLAST FOR A FEW MINUTES then off.")
I just noted this same consideration..... that systems can be had, and likely will become more developed out; that modulate the output to the granular data going in..
It's called modulating.
need to run a duct from basement to top floor and have a separate fan to move air from one to the other depending on what you want
@@gg-gn3re That would be nice if zoned HVAC could do that. All I have are manual baffles in the utility room to enable/disable the registers in the basement and top floor. (Separate baffles for the two floors - the main floor stays open at all times.)
I know there are more granular zoned systems, or even multi-mini-split systems that can move refrigerant between rooms to do that, but they’re expensive.
@@AnonymousFreakYTYea they are, I was being literal. Run a separate duct entirely from your system and then just have some switch to turn it on/off it's likely you'd want it on almost 24/7 so I'd just run it separate. As you say there are systems that can handle this kinda thing but they're 10x the price
As an HVAC-R technician, thank you for pointing out these issues that this industry needs to address by training techs to do manual J, sizing equipment properly, and not being salesmen first, would do so much to help move the industry forward in a more efficient direction. I'm working on starting my own business this year (hopefully), and I have the same mentality as you, more pumping, more now, at reasonable prices.
The industry isn't there to be more efficiwnt though. Like every other industry it is there to pick as much money out of peoples pockets as possible.
@rogerk6180 While that may be true, by offering more efficient units and service, you would, in the long run, earn more from repeat customers rather than the highway robbery some companies are responsible for these days. I see what the company I work for charges for almost every job I run, and it's nauseating at best what they get away with charging in most cases.
@rogerk6180 It's the mindset that needs to change, and unfortunately, that's far easier said than done. That's why I hope to make a small ripple in the big pond of companies in my industry, it might not do much, but it could start things moving in the right direction if enough people start talking about it.
@@joshengelbrecht1310 the problem is people no longer want to know anything anymore. All they know is more bigger and more expensive is better and having more expensive is more bragging power.
Picking the cheaper option must mean it is worse or it makes you a cheapskate.
So the one who offers you the biggest and more expensive option must be the better option. And companies are more then willing to accomodate that.
In the past people had at least some superficial knowledge about most things and thus knew what they needed and where looking for. Most people can't even put up a lightbulb anymore it seems and are so conditioned that everything is some complicated safety risk that it needs some high payed profesional to do it. Even though most things are done by random dudes that are sent over as a profesional that barely know the right end of a screwdriver themselves.
I see a lot of americans moving to the netherlands where i live, and how many basic home tasks they request a "contractor" for that are just simple things every single person here knows how to do themselves in 15 minutes is shocking. I imagine your grandparrents did these things themselves around the house as well, but somehow culture shifted where this skill was lost or made to look so scary that people are de-incentivised from doing them themselves.
The amount of light fixtures i put up and shower heads i have replaced for bewildered american neighbours is just shocking lol.
That is something your dad teaches you how to do when he does it at home or the first time you move out of the house here in the netherlands.
There is a cultural difference for sure.
Ignorance breeds exploitation. If you have no idea what a job actually entails and seems mighty difficult you can basicly ask what you want to do it for other people.
As an hvac master myself, in upstate NY, a lot of manual J up here are way undersized lol. Not the other way around.
I had one set of plans with Emmanuel J that said they needed a 40000 BTU furnace for 1600 square feet of house. Yeah right.
You're not taking into consideration air exchanges, dehumidification, and enthalpy.
I do see a lot of oversized equipment out there though. Good video!
I'm in Canada and love my cold climate heat pump. We have 15 kW of backup heat strips which I'm now thinking are wayoverkill and they have yet to be used despite outdoor temps dropping to below -30 last year. They definitely didn't get used this year as we barely had winter. Heat pumps are amazing. Highly recommend!
@heymike7037 How north of a Canadian are you?
@@walkurone North enough that we get weeks long spells of -30.
must have a really low heat loss home.
@@Jon-hx7pe not really, it’s from the 1960’s.
I'm glad you addressed short-cycling Air Conditioning...
Most people don't understand this.
One other thing that cannot be understated is air leakage and window radiation, and how much of a dramatic difference it can make to the heating or cooling efficiency of your home. We live in a more mild climate and only have a reverse cycle air conditioner in our home (a.k.a. a heat pump).
I reduced my power bills by at least 20% month for month from one year to the next by only adding tinting on the east and western facing windows along with redoing all the air seals on all the windows and the external doors and actually adding one to the attached garage.
A downside to living in Australia is that a LOT of buildings over just do not take thermal efficiency into account and the building codes reflect that mindset.
Thank you so much for producing this video (and all your others too)!
The shorter format, specifically designed for sharing is particularly useful.
My 1100sqft 1940s single story house in a mild/moderate California climate came with a 3ton 36kBTU gas furnace, which only heated half the house in short bursts. Fast forward 7 years, $15k in overpriced “guesstimate sized” hvac with new ducts to the rest of the house, installed in a day, and was never commissioned correctly… and my home was still uncomfortable.
As an experiment, two years ago I DIY installed a 1-ton 12kBTU VRF mini-split heat pump in the central room of the house and it’s capable of handling ALL MY HEATING AND COOLING NEEDS! It keeps my house comfy at 69degrees, and does so using 700-1000watts, near silently, and cost me < $1000 to DIY install (including buying all the tools). The $15k 3ton gas furnace with 14 SEER heat-pump system could technically sit idle or be removed.
@Technology Connections - Ideas for followup videos
- air sealing / insulation
- oversized MERV 13-16 filters
- IAQ - radon, CO2, particulates (PM2.5)
I’ve fallen down a deep rabbit hole of knowledge that typical hvac installers are not trained/educated about. Thank you again for putting out all this content. The residential HVAC industry needs to get learning and implementing best practices quickly, so we can collectively move away from burning things for heat, save money, and all live more comfortable/healthy.
Yes! Air sealing and insulation should be at the very top of the list before addressing HVAC!
This is my life in the trade!!! I see oversized every call.
This is amazing!!! Thank you
Hot water baseboard system here, in northern Pennsylvania. Temps rarely get below 0°F and VERY rarely down to -15°. The old system was a 140k BTU monster and maybe in the 70% efficiency range. We replaced the windows, reinsulated the walls, and added insulation in about 2/3 of the attic; the new boiler is 90% efficiency 80k BTU, and also heats the domestic hot water. If one or both of the thermostats are calling for heat (and the HW tank isn't), it checks the outdoor temp, and the water temp coming back from the house on the return side, and does some of that "math" stuff to determine how hot the output water should be, and fires the modulated burner accordingly.
When it was first set up, with a low-end design temp of -15°, on a 0° but windy night, it couldn't keep up - the temperature curve had it still holding back a little at 0°, and the house couldn't get above about 63-65°. I reprogrammed the curve to ramp up to full throttle as it approaches 0° instead, and that did the trick.
I worked in the oil heat industry for many years. Everything you said is exactly what we attempted to teach our customers. We always did load calculations and more times than not recommended replacing old units with smaller more efficient units. People have been brainwashed that "bigger is better".
Design load is immensely important, especially for cooling. Short cycling the AC means you're not dehumidifying the air. Half the work of AC "should be" dehumidifying. You'll feel comfortable at a higher temp if the humidity is lower.
The same holds true for heat except you want to introduce humidity. If you have a humidifier installed onto the heater but it short cycles, you're not benefitting from the humidifier as much as you could be. As you stated, you want your HVAC system to run 100% (all day) when the temps hit their extremes for your area. In the Philly area we used 0F for heat and 100F for cooling. If your HVAC is cycling on & off on the most extreme days, it means you're literally throwing money away the entire time it's running... All year.
Thanks for bringing so much good info to people who crave it.
I watched the full length but wanted to like and comment here for the algorithm.
Thanks, Alec!
Love you!
they're different, I watched both
We replaced just the outside unit with a heat pump. I think the retail price of the unit was about $3-4k. Our HVAC installer charged us $9,000 and it took an understudy only 4 hours to complete. More attention is needed on the price gouging in the industry and the lack of willingness to provide fair pricing. That said, we saved a good $15k by not also upgrading the attic unit (blower). Replacing it would have necessitated 240V wiring and another breaker. We kept our gas furnace and have dual fuel with gas as the backup. We have a 3 ton unit for a 2,600 sqft modern home in California. Every calculator online seems to think I need a 4-5 ton unit, which to me is absurd. I don't think our heat ever ran more than 2-3 hours in a single day this winter.
You can't buy a furnace or a heat pump without going through a licensed HVAC dealer.. It's literally illegal in most states.. It's common in all of the building trades for the contractor to double their money on equipment and material sales.. Plus, charge for installation of the equipment and materials they sold you.. That's just the way it works.. If you don't like it, spend 4 years doing an apprenticeship, tens of thousands of dollars on tools and equipment.. Pass all of the test you have to take to get licensed.. Then spend 3 or 4 days crawling through your crawlspace and attic to do the install yourself.. I'm an HVAC technician.. There's a lot of overhead involved that we can't charge you for directly on the bill.. We don't make as much money as people think..
@@MarkLada My HVAC guy (owner of a 3-person company) lives in a million-dollar house and has a collection of classic cars. He does just fine with his profits.
@KiwiandPixeltheParakeets There's too much competition to over inflate bids like that.. You wouldn't stay in business long at all that way.. A couple of hundred dollars can be the difference between getting a job and not getting a job.. Especially if it's a municipal contract or commercial job.. We make a good, honest middle class living, but we have to work our tails off and sacrifice our bodies to make it.. I guarantee you most people wouldn't go in some of the places I have to go into on a daily basis.. Crawlspaces so tight you have to drag your face on the ground to crawl through them.. Attics so small that you have to lay across 2x4s and work on your side all day.. Just wait, if you think HVAC stuff is expensive now.. The government keeps imposing stricter and stricter regulations on us.. Equipment prices are going to more than double in the next few years..
@@MarkLada Maybe you don't make much as a technician, but your company owner is probably raking it in at your expense. Perhaps with all that training it may behoove you to go into business for yourself. Just a suggestion. None of what you said negates the fact that HVAC owners are absolutely raking it in with sky-high pricing.
I'm just hoping for a cut that is just the B-roll of heat pumps, which will of course be the [condenser version]
I clicked on the link and got to the condensed version. Then you got me interested in the extended version, so I clicked on the link. Then you got me involved in the condensed version, so I clicked on the link.
Alec invented perpetual motion video, huzzah
I think I enjoy this calmer presentation more.
I'm sure many will! I actually kind of want to offer the choice here, and I'm curious to see how this goes.
I enjoyed this as well, and I can totally see why it is necessary.
I like the rambly version more, but this is the one I'm going to send out to several friends who are looking at hvac upgrades in the near future.
@@TechnologyConnextras I agree that I find this more compact version more enjoyable, however I love the fact that you are offering both, mostly because for a topic that I care more about (like the pinball machine videos as I find it fascinating) I'll probably choose to tune into the longer format video
As someone who is a fan of the channel but doesn’t have any background knowledge in this field, I also like this video more because it’s a lot easier to follow.
1. Your heating/cooling system is sized for extremes, the coldest and hottest days of the year. So it will be "oversized" 360 days a year. Because if its not, the end user will complain. We wouldnt size them like that if we didnt need to.
2. Equipment goes by tonnage, a ton of cooling is 12,000 BTU per hour. Equipment models usually step up by 1/2 ton, sonetimes 1/4 ton a time. A house may only need an extra 500 btu an hour to meet the extremes, but the next possible size up may be 3k-6k more btus.
3. Modulating systems that can adjust capacity depending on need do exist, but they are more expensive.
4. If you want a "normal" size system, especially a heat pump, keep in mind that it may not keep up in extreme conditions, and you need to leave them on 24/7. If you turn the thermostat off at night or when youre at work, they will not be able to get back up to the desired temperature for hours.
My 1970's bungalow (*) in frozen capital of Hoth (Winnipeg) is heated with resistive electric forced air furnace. I've wired sensors everywhere. I can say with much certainty a single 5kW element will easily maintain my home at 20C through our coldest winters (to your point, it may not recover from a 3C overnight setback when it's -30C outside - but the temp won't drop). My 3x5Kw furnace rarely runs the 3rd element as it stages up (only when recovering on cold mornings )
(*) Walls are original 2x4 R12. Attic is R60 (thanks to recent utility rebates on insulation). Basement is R20 and windows are triple pane.
How much are your power bills? Is there a reason you don't have gas heat where you are in Winnipeg?
Winterpeg! I grew up on the Prairies - the cold can be impressive for sure.
@@kw_boeing $225/ month. Switched when gas was all time high and hydro was less. Cost of high efficiency gas was more than double an electric. Switching from the original gas to electric did not increase my gas+ electricity bill. And I'm comfortable fixing an electric furnace in the middle of a cold winter night. Not comfortable touching a gas furnace with all its sensors and confusers.
The way that heat loss works, it will always be able to recover back to design temperature. It will take longer with less power, but it will get there.
The part of me that loves your stuff wants to listen to the full version
but the part of me with things to do is happy for the condensed one. good job. now to fill the condenser with new refrigerant..
Shoutout to all my fellow people who just watched both versions back to back
Thanks for making a condensed version. I want to hear about your topics but I don’t always have an entire hour to spend.
Actually came to watch the condensed version just now because happen to be in a situation where a friend could benefit from the information. So thanks again, not only for the original version but also for this more shareable version!
Great video! I thought I was the only one goofy enough to add up space heaters to verify how much heat pump capacity I needed! In addition to adding up space heaters, I also ran a Manual J calc for my house. Then I looked at the spec sheets for my heat pumps to make sure I'd have enough heat on my coldest nights. The mini-splits don't have backup resistive heating, but I do still have my science experiment space heaters in case I ever need them!
You might have covered it in the longer video, but it's worth pointing out that heat pumps' output ratings are benchmarked around 35-40 degrees F. At 35 degrees F I have 34 kBTU/hr (about 3 tons) of heating. At -13F, I'd only have about 15 kBTU/hr (about 1.25 tons). In an extremely cold environment, that would be one reason to size the heat pump up.
As a non home owner, I'm going to go for this version!
Btw, we really enjoy your videos. One of the best channels on TH-cam!❤
The platonic ideal of a educational TH-camr
I laughed so hard when you said, 'even Christmas lights' 😂😂
Oh yeah, we never found out why 😮
@@DaveTapley watch the full version for that.
@@DaveTapley In short (and simplified because I don't quite remember) he was worried about pipes freezing in a crawlspace, as the air ducts wouldn't provide heat anymore and the space heaters are overkill for such a small space. So he added 100Watts of Christmas lights to provide heat (and festive atmosphere) to those places.
We in Holland use a gasheater to warm central heating water. I adjusted the temperature from 80 degrees back to 55 and the total output in kW back to 25%. Saves tons of gas, only takes a little longer to warm up the house.
same here, the factory default of our boiler is 75°C for the heating and 60°C for the hot water in the shower, like who the hell wants that hot of a shower?!?
@@GameCyborgCh Hmm, my boiler has a pre-mixer, this allows me to heat the water in the boiler to 75C and get away with just a 300 L boiler running for two of the cheapest hours of the day and still get enough hot water for three teenagers and a wife. :)
can you explain what you mean by adjusting the total output? Does your furnace offer different performance levels?
@@weppwebb2885probably a PID controlled gas valve
Used to be, houses leaked a lot and were poorly insulated. The furnace had to overcome that or homeowners complained loudly. So massive oversizing was the norm.
Nowadays, they are supposed to be well built, well insulated, and well sealed. But there are so many homes built to code minimum, that most arent correctly insulated, sealed, or even properly built.
So they are still being oversized. Heat contractors arent being paid to perform a full house blower test and thermal imaging to see what it really needs. And then reccomend all the fixes be done as part of the install process.
Take a thermal camera around your developement at night to see what it looks like. Then check older developments and single resident homes, apartment buildings, and even commercial buildings.
(Old man grumble 1st thing in the am without coffee...)
100% with you. When I bought my (now 115 year old) home, it had a 100KBTU/hr oil burner feeding steam, which was, generously, 75% efficient. Originally, the house had a central coal burner. The house was not tight, the windows were original, loose, and several broken, threr was little insulation. First thing was add insulation where easy and plug the big holes. I had no problem the first winter with a 22KBTU/hr ventless gas unit and a 1500W electric to back it up (don't judge me on the ventless unit. The house STILL isn't very tight despite 15 years of work). When I did the main system, I ran a manual J, got 44KBTU/hr, not considering the added insulation and replacing the windows. I put in an 80KBTU/hr, 96% efficient condensing hot water unit with panel convectors to replace the steam sectionals that also does domestic hot water with a 30gal tank. External sensor sets the firing rate based on outdoor temperature. The inspector (lets call him "Bob") wanted to fail me because the ruie is a replacement must be at least as big as what is replaced. He couldn't show me the rule. I showed him the calculation and he said that Manual J is BS. Those guys that wrote it don't know what they are doing. But if I want to be cold and have pipes freeze, it's my problem, and signed the tag. Never a problem. I can hold 75F when it is -15F with 30Kt wind. For 22KBTU/hr. And be able to shower, wash dishes, and do laundry all at the same time. I can't het pump, though, as I have a 60A service (from the post-WW-II upgrade) and there is no capacity for anyone in the region to upgrade. Don't get me started on the local utility....
My new house got installed with a heat pump per my request thanks to your videos so thanks Alec! Having that unit also saved me a lot of space in my garage which is a huge bonus for me since I actually use my garage to store my car. I move in to my new home in about a month and I can’t wait to get all nerdy with my guests about my ac unit that I’m weirdly proud of.
The reason why summer AC needs the same amount of power for a smaller temperatzre delta is humidity or more accurate the dehumidification that happens during cooling.
As you covered there's A LOT of energy in the latent heat of vaporization and the same goes for the condensing part and that water from the evaporator doesn't go through another heat exchanger. In 99.9% of the cases that cold water will be dumped straight out of the house.
I used to live in a middle apartment with people above, below, and on 2 of 4 sides of me. Only 1 small and one long outside wall. I NEVER turned on the heat, even in the dead of winter and the temperature was fine. Didn't save me any money, though, because the whole building's electric bill was split evenly. 😂
Now I have an approx 1400 sq ft detached house, built in the early '80s, and our 24k BTU heat pump seems to work very well except for those few days in the dead of winter when it is really REALLY cold. And on those days my heated blanket is a great friend. ☺️
Hey bud, we have the same issue over here in the UK. My house which is less than 5 years old came with a gas boiler (furnace to you guys) and we didn't get the option for a heat pump even though we bought the house before it was built. That aside, I have reduced my boilers temperature (actually on the boiler) down to 38°c which is more than enough to heat the entire house with radiators to 21°c. The manufacturers recommend 60°c which is crazy as it is a condensing boiler that reclaims lost heat from the condensation created when it's on. The lower the temperature, the more condensation, the more heat is reclaimed, the less gas and the more economic it is to run.
A boiler is a boiler here as well. A furnace, in our parlance, doesn't boil anything. It typically heats air with natural gas burners through a heat exchanger, and then that heated air gets forced through air ducts to the entire house. Unless you call such a system a "boiler," which would be wildly inaccurate in any country.
@joesterling4299 oooh, I never knew that. I actually thought that gas boilers and furnaces were the same thing except in the US they heated the air because you all use air-conditioning too, and it just made more sense than installing radiators and ducting for air-conditioning as well.
We simply don't have furnaces (at least not in houses) over here.
how well does it heat when set to 38 after the heating has been off for the workday? that must take hours to get back up to temperature.
@somethingfunny6867 I have set a "fall back" temperature on the thermostats to 16°c although it's never dropped that cold. Even if I finish work early and check the temperature, it's no lower than 17.5. I'm guessing my house is well insulated. There's a channel called heat geeks. They mainly focus on heat pumps these days, but older videos focus on gas boilers and setting it up correctly. I was thinking of buying weather compensation, but before investing in getting it installed, I tried lowering the boilers temperature (which is what weather compensation does depending on the outside temperature) and found that 38°c seems ideal. It will be slower to get to 21°c than having the boiler set to 60°c or more, but it also heats up more slowly, putting less strain on the system, and it doesn't over shoot the target temperature.
You can get more geeky by adjusting the flow rate to each radiator, but that is something I give up as a bad job. I have all my radiators fully open, and although you think I will be heating rooms I don't use wasting energy, the heat from all the radiators goes into heating the entire house. If you turn off a radiator to 1 room, the other radiators actually need to work harder to heat the rest of the house up as the heat will transfer into the colder room. It's all about energy states and equilibrium. You might as well have all radiators and rooms at the same temperature since it gives you more internal thermal mass to keep the house warmer for longer.
I appreciate the shorter version! Sometimes I am deeply fascinated by a topic of yours but can’t quite commit to the beefy ones. I am LOCKED IN for this one
As a Brit, I remember growing up in the sixties and seventies with gas being charged in british thermal units (BTUs to you) but even then, electricity bills showed kWH. I studied physics to A level, using text books dating from the 50s, but never heard "ton" used as a heat unit, until the mid 80s when I shared a university flat with some American exchange students who were studying engineering
Excellent video! As a homeowner than may need to replace my gas furnace soon, all this is good the know.
I had an early model Rheem heat pump back in the late 70s, to augment my gas furnace, and unfortunately it was inadequate to heat my home below 35°F-40° F and I replaced it with a 3 ton A/C unit. Good to see the technology has gotten much better. Having a large 3 acre lot, I may also explore a geothermal system.
@dennissmith8199 - it is normal for conventional heatpumps to not be able to give enough heat much below freezing, those units are still very useful in shoulder seasons and worth getting instead of an a/c when doing equipment replacements. they are still made. there are plenty of mild days during the heating season. Cold climate heatpumps are loaded with electronics, that is the down side. this being said, a 70s heatpump would have been like 5 hspf and not worth running compared to gas, new ones start at about 8 hspf efficiency.
Explaining that a 'reverse-cycle' is just an 'air-conditioner' is almost as hard as convincing someone a 'swamp-box' is bad.
why are swamp coolers bad?
swamp cooler depends on climate
I'm very glad that everyone is an expert on HVAC now!
More pumping. More now.
I love how you always have your lava lamps flowing in the background. I wish you would do another lava lamp video!
funny thing, not really related to the content of the video. I saw the notification for this video on my phone and saw the words, "condensed version" but when I got on my computer and logged into youtube, it recommended the full version. thinking I was watching the condensed version, I was.... a tad worried that the condensed version was an hour long. So thank you for linking to the condensed one in your full length video.
I'll be honest, I live in a trailer with no central HVAC system and as far as I'm concerned, my housemates horribly overuse space heaters.
I live in a climate where we're lucky to get one snow a year and even when it snows, it's usually slush. We didn't even get slush this winter and had 70+ degree days in February and the coldest nights barely got into the 20s.
Aside from avoiding chills getting out of the shower(which high air temperature doesn't really accomplish anyways since we only have like a 15 gallon water heater that's inadequate for bathing), the only time I'd bother with the space heaters if it was up to me was keeping the pipes from freezing on the rare night it freezes(And honestly, it's a bit of a head scratcher for me that modern plumbing isn't designed to account for the expansion of water as it freezes. The rest of the time, I'd rather just bundle up in my favorite hoodie it's too hot to wear most of the year or cocooning myself in blankets and let my metabolism keep me warm.
Sadly, this tin can also heats up to over 100 in the summer and most of the windows are too small for a proper window AC and where I live is too freaking humid for evaporative cooling to work, so I had to fork out for a portable AC... and linking back to the subject of the video, the smallest, cheapest one I could find is advertised for a room two to three times the size of the room it's in.
One other way you can test if your house is ready for a heat pump, provided that you’re able to change the temperature of the heating medium (water through radiators or air through ducts): lower the temperature and for shits and giggles see how low you can go while maintaining comfort. I’ve been able to lower mine from the default 70 Celsius down to 45 Celsius. And now that I have underfloor heating I managed to make do with 35 C.
This is a good test for hot water systems (and also increases boiler efficiency) but it doesn't work for forced air furnaces. Furnaces output a fixed amount of heat regardless of the output temperature.
14:00 other method : during an off we, read your meter when you leave, and come back, let your heater at 20C, and time how long you were away.
The test must include at least one night, possibly 2.
Check the average external temp over the period.
Now you can calculate, for a given delta temp ( internal - external ), the energy used over a given time . That gives you the thermal resistance of your house.
Your fridge was working ... But was contributing to heating so does not matter.
A sizing rule of thumb an ASHRAE old-timer told me was used long ago... Stand at the curb in front of the house. Hold your had up, fingers up, "stop" style. See how many fingers covers the width of the house. that number is the tons of heating needed.
In FL I've only ever had a heat pump. I don't know it any other way. I remember heat pump advertisements back in Missouri all the way back in the 80's, though. Had no idea they were considered new or exotic.
I'm a Hvac mans and leaning the Manual J and Manual S right now and have been in the industry for only four years. I have never been told to not tell a customer what a heat pump is or how they work. This is not a secret. They are great systems. Sounds like it's just bad companies or a bad sales man that actually picks the equipment to be installed. A good sales man will inspect the duct system when sizing equipment. Nothing should be assumed that anything is okay and we (me at least) were taught this in the Manual J class. Not every Tech knows how to do these calculations and its not their fault; it is the companies fault for not providing a qualified person to take the time and effort to do it in the first place. A lot of companies just tell their Techs to (just make it work or just sell this or that rather than fixing the root problem). You need to find a good company and do some research as they are out there.
In south FL, most homes down here have undersized duck work. Why? No idea but we all know about it and yes it causes problems to the whole system. But it is slowly getting fixed with new construction. It is very expensive to replace an existing duct system and the vast majority of people cant afford it. Duct sizing is just as important as finding the right tonnage of a AC system.
A senior tech once told me "AC is going to become a commodity for the rich" and I truly believe that.
One thing you need to consider is the duty cycle of your furnace. If it’s not spec’ed for a 100% duty cycle, you need a higher BTU/hr rating.
I am a mechanical engineer that sometimes dabbles in HVAC. I am not in any way going to argue that the HVAC industry is "good" or that heat pumps are not worth the investment. However, I am going to argue that oversizing a gas heat furnace is not as detrimental as is being argued in this video. Yes, an oversized furnace DOES produce more heat than is required, but for less time. it will still produce the same BTU/hr on average that a furnace sized exactly right will produce. This was demonstrated by his thermostat calling for heat only a portion of the time but maintaining a near constant indoor temperature, even though his furnace can produce 4x the heat required to maintain the indoor air temperature. Yes, if you had an 80,000 BTU/hr furnace that was running constantly, that would be bad as your house would quickly heat beyond what most of us would consider livable. But on those wicked cold days, the 80,000 BTU/hr furnace is only running 25% of the time, producing 20,000 BTU/hr average heat output.
I deal mostly in industrial applications, so I can't speak to residential equipment costs. But in my experience, keeping all other factors the same - primarily the amount of air volume the unit can handle - the cost of the unit does not change much by just changing the heat capacity. Meaning, you're not loosing more than a few hundred dollars by going with a much larger furnace than is strictly required. The reason that this matters is that even though air is a relatively light substance - compared to water or bricks - it still takes energy to move. If your furnace is moving air around your house 100% of the time, the blower motor in your furnace is going to be drawing power for that entire time. If you are only moving air around your house 25% of the time (when the furnace is running and producing heat), your power bill will be less. It will also reduce wear and tear on your equipment (bearings, belts, motors, etc.) which increases the useful life of the equipment.
If your furnace is producing too much heat all the time, no one would argue that its a good thing. Our furnaces should be producing only as much heat as is required. But if your furnace is capable of turning on and off more than once a day, producing more heat than your structure is loosing to the cold outside does not pose any problems. The furnace simply turns off when not needed, reducing the amount of power required to move all that air around your house.
I learned so much when replacing my heat and AC units. We have an efficiently sized unit for a 3600 sq foot house and when first installed seems too “weak” for the house when you’re used to typical air blasting from the vents.
My dads furnace is so oversized that when the heat turns on, loose papers will fly off the coffee table
Efficiently sized units should run longer with fewer total on/off cycles - especially when running the AC as it provides not only cooling but dehumidification
The difference between the tonnage required in heating vs cooling mode and the outdoor ambient temperature is because temperature isn't the only heat load in your house. The people in it put off heat, your appliances put off heat, your electronics put off heat, and most of all there are direct and indirect solar loads that hit your house on a daily basis. This means you actually get a helping hand in cold weather but a lot more energy to reject in hot weather.
In my townhouse there's a boiler for heat and hot water, a heat exchanger in air handler to transfer that heat to the forced air system, and an AC unit. It would be straightforward to simply replace the current AC unit with a heat pump (and that's my plan). With the boiler still online there's no downside to having the heat-pump a bit on the small side. Further, in my particular system the evaporator/condenser is before the heat exchanger. This means that you could conceivably run heat from both a heat pump and the boiler simultaneously, allowing the boiler to be down-sized as well. My system here in Toronto was more reasonably sized than yours with the heat exchanger rated to 40k BTU and a 1.5 ton AC unit.
I've watched both of the other videos so I'm mostly just here for the algorithm. Love your work!
Thanks for the tips around pricing - I should have expected some of these things.
I just went on the carriers website and they make the following statement. “Typical residential gas furnaces will be available in various sizes between 44,000 BTU/h and up to 120,000 BTU/h.” It’s possible that the high-efficiency furnaces may not come in sizes smaller than 60,000 BTUs. So you may have gotten the smallest furnace that you can get.
It might be a good idea to talk to someone in the furnace manufacturing business to find out there take on this.
Good points. My 1200 sq.ft. house, in northern CA. had a 100,000 BTU/hr. furnace installed back in the '70s. I made a video about that furnace a few years back titled:
"Getting the Old Fraser Johnston Gas Furnace Running"
On-line calculators estimate a 36,000 BTU/hr. rating would be sufficient. I suspect even 20,000 BTU/hr. or a 2 ton heat pump would be more than adequate. I don't use the furnace, instead heating the house with solar hot air with backup from a fireplace insert.
Fantastic video and I will share this every single time I get pissed off about HVAC contractors.
Bless you my good man.
wait, the short version is on the second channel? what the heck?
Snow!
I feel snow does not get the attention it deserves. It only takes minutes to clog an air sucking heat pump up and it takes perhaps 15 minutes defrosting itself. It will lose that battle. The solution seems simple: put a little awning over the unit.
You hit the nail on the head when you said that HVAC companies get a rough idea then order bigger. So glad I'm not in the industry anymore
There's an HVAC guy in Lansing Michigan (All Star Mechanical) who has had a couple rants about this. Apparently his small company is the largest installer of 40,000 BTU furnaces (the smallest Trane makes) in Michigan. Trane sold 83 40k units in Michigan last year, this guys small shop bought 37 of them. In the last year Trane sold 390 80k BTU furnaces. This guy bought one of them.
I keep my thermostat set to 15 C (~60 F) and use a portable heat pump just to heat my office during the day. The usual inefficiencies of portable systems barely matter when moving heat within a closed system, and heat pumps are most efficient across small temperature gradients, so it’s 2x super effective. It’s basically using the same principle as multi-apartment systems discussed in the follow up video.
Technically my heater needs to work a bit harder to stay above 15 than if I was on vacation, but during the day just passive heat usually will get it close, and by now (March) it reads 16-17 before I even touch the thermostat in the morning.
Years ago, I bought one of the first high efficiency furnaces. They only made on size (75000 BTUs) which was way too big for my house. The installer said they would put in a restrictor plate to bring the furnace down to 35000 BTU. You might want to check and see if they make a restrictor plate for your furnace to bring it down to 20000-25000 range.
I work with heat pumps for Massachusetts' energy efficiency program and I wanted to reply to something you pointed out, using existing ductwork for heat pump systems. It is very rare that old houses (i live in the north east, so most of our houses) have ductwork that be utilized by a central heat pump. According to the policies our company uses, each floor needs to have a return duct (which disqualifies most 2 story houses) and the ductwork often just isnt large enough even if they do have a return duct. I dont need to know the heating load to run this calculation. Any home we can't fit central heat pumps in we pivot to ductless mini splits.
As far as sizing heat pumps, it is slightly more complicated than you portray but you are almost right on the money for the sizing range. The thing to keep in mind for DMS is that the snallest head you can get is usually 7,000 BTUs, and the most heads you can get on a compressor is usually 4. This means you often end up oversizing the head in one room to cover the heating load of an adjacent room which is too small, and often means oversizing more than just the sum of those two rooms to make sure the heat properly spreads, especially in older homes which trend to having more but smaller rooms with less continuous airflow between them.
The other thing to keep in mind is that heatpumps really shine when they are holding a home at a continuous temperature, meaning that the more insulated your home the more you will benefit from heat pumps rather than a one stage system. Almost every state has an energy efficiency program offering MASSIVE subsidies for insulation work, my state targets a 1 year ROI on any money put into insualting a home, so if youre asked to oay $2k for the insulation work thats also likely what they expect you will save that year. Everybody should be having these assessments done, they are free in most states.
I tend to freak out and feel like my heat isnt working when it kicks on and off every 10 mins when it's super cold out.
I would really appreciate you used the same units for thermal power. You've been alternating between BTU/h to W to Tons as if everyone knew the conversion factors. I'd say you stick the audio to one unit only and put the converted units on the screen for whoever cares.
Another excellent video! When I have more time I'll watch the rest of the long version - gotta know what the Christmas lights are for!
Gosh, if only there was a TH-cam channel that I could watch to learn more about these heat pumps somewhere.
Speaking as a (now retired) 38 year engineer - electrical rather than HVAC but the idea is the same. The principle often used is: if you oversize there might be some grumbling about price. If you undersize, lawyers get involved and that is a bad thing for the supplier and designer. Your point is very valid, we should design closer to actual requirements, there just is a tremendous aversion to being sued.
This and many other yootoobers have never heard of Chesterton's Fence.
In my previous home, we had a 40kW heater running on diesel. We replaced it with an 8kW pellet burner. Saved us lots of money, was much more quiet and easier to run. And we were never cold. If we'd have to do the same today, we would have gone for a heat pump in stead of course.
I was worried about being up sold when buying a furnace but was reassured that there's minimal price difference. It's mainly just the gas orifices that differ between similar sizes, which makes it even more strange that this is such an issue. I found a company that said my old 80k btu was oversized and recommended 60k btu. It sounds like AC/heat pumps are a different story though.
One option with an oversized 2 stage furnace, either because a heat pump has been added or just in general: Connect single stage thermostat wiring to just the 1st stage/low heat of the furnace and set the furnace to 2 stage/manual mode so that only low heat is used. Only if it's adequate of course which could be calculated based on furnace specs and would result in more even heating instead of the furnace's auto mode going to stage 2 unnecessarily. Could be useful for older thermostats but may not be as much of an issue with some smart thermostats. Mine tends to use stage 2 too quickly but I may try fiddling with the smart thermostat settings instead because stage 2 is nice for quick heat recovery when needed.
We had two contractors quote for installing heat pumps this year, to take advantage of a government grant. As is usual in the U.K. we have a condensing gas combi boiler which provides hot water for both hot taps and radiators, so we were quoted for an air-water heat pump systems. Since our existing radiators were sized for high temperature water flow from a gas boiler, every one would have had to be replaced with a larger radiator to cope with the lower temperature output of a heat pump. Replacing every radiator with and even bigger one would require a lot of work, so even after the grant is taken off the price, the total wasn't much less than just having a Ductless mini-split air conditioner installed in every room, and these would give us cooling in the summer as well as heating in the winter.
So, we decided that it makes more sense to keep our Gas central heating for hot water, and backup heating, and invest in air conditioners for the bulk of our heating and cooling needs. We wont get the rebate, but we get a lot more functionality for a lot less hassle and not much more money.
Oh, and it's worth mentioning, before anyone tries to fit an AC unit themselves, you should definitely check your local regulations. In the UK, you need F-Gas certification to do any work on A/C or heat pump systems.
What an impressively brief video about efficient home cooling!
Also in Chicago (Oak Park). Just put in a solar energy system and looking to completely get rid of gas. This really made me feel better about replacing our 20 year old oversized furnace with a heat pump like I have been planning!
A oversized gas furnace can have its primary heat exchanger crack from its short cycling like mine did. I went from a 75,000 btu furnace to a 45,000 btu model which is more inline for my sometimes very cold NW Wisconsin home. I’ve seen it get down to -38f a few times up here.
if you want to cut down on the capacity of the furnace, just plug the outer burners on the furnace. all you have to do is pull the burners out and take out the orifices on the manifold( screwed in/ pipe thread) and install plugs ,and reinstall the burners. we did that on furnaces that had bad heat exchangers, so the customer could at least operate the furnace until the weather got warmer, and give time to get a replacement furnace ordered, and installed. the outer burners being shut down will not cause problems with the hot surface igniter, flame sensor or the flame runner. .the regulator in the gas valve will automatically adjust the gas pressure to the manifold. you got a furnace that is the smallest unit made, and is still too big, all I can say is "OH WELL "at least it is not the other way around where it is under rated.!!!! I would not remove the furnace, as it would make for a nice back up heating system( second stage), incase the heat pump would fall on its face
@TechnologyConnections I loved this video. I would love to hear to dive even deeper and talk about SEER ratings along with geothermal technology
Oversized everything is a big problem, Alec! Thanks for focusing on the HVAC! Over sizing of heating equipment is rampant
My only issue with heat pumps is an issue with forced air heating in general: it never addresses radiant heat and mean radiant temperatures of exterior walls.
For one particular cool spot I use a mere 100w ceramic brooder lamp and the comfort level vastly improves with little change in air temperature.
But that’s a subject for another day
There's a practical factor involved in using either resistance or gas heat strictly for peak-day supplement. That imposes a huge (system-wide) demand spike on the generating system and distribution grid that causes peaking generators to come on, running at the highest cost per MWh. That cost isn't recovered in the few hours of energy sales at "normal" kWh rates. Utilities, in their own defense, could then decide to add a 12-month ratcheted demand charge (as they generally do for commercial and industrial customers). After all, the entire grid has to be sized for that design-day peak load.
A couple of factors you are forgetting. 1. If your neighbors house is warmer than yours, you will be stealing heat through the walls. So if you have an elderly neighbor that likes the heat cranked your going to need less btu's to heat your place but if one moves in that likes it colder they will be stealing btu's from your unit. 2. Most places are designed that you can move a couple of degrees aka gain heat which is more than btu's needed than to just maintain temp. This is done for power outages or because people keep their house much colder when they are not home.
I've been surprised before by how little HVAC capacity a well-insulated living space actually needs. My current apartment is about 700 square feet and in an older building, but one that was modernized with (at the very least) energy efficient doors and windows. I don't know the actual heating and cooling capacity of the HVAC, but when I moved in, I noticed that the condenser was tiny, possibly the same size as the condenser on an extra large window unit. I'm used to big barrel condensers, even for similarly sized apartments, and was worried it wouldn't be able to cool the apartment adequately, but this past summer it worked just fine.
Larger 120v window AC units are over 1 ton of cooling capacity. With decent insulation this is plenty for a 700ft2 apartment.
I use a heat pump (in Florida) and its so nice.
I also have an HVAC guy thats honest and downsized my unit (saved me a few Gs) and it cools and heats my house just the same as the old unit but also uses about $30 less of electricity in the hot months.
I had that problem. when my AC came on this huge blast came with dramatic loud noise. I had a friend over who used to do this kind of engineering before he retired. He looked up at my vent when it came on and said "your AC unit is too big." Yeah, we were sold more expense than we needed. I live in the South, so we RARELY need the heating coils.
I just went through this to take advantage of the recent Canadian rebates for heatpump installs. I had a ~75,000 BTU furnace and a 3 ton AC. It was replaced with a 60,000BTU gas furnace and a 2ton heat-pump. It's all setup so the smart thermostat uses the furnace when the outside temp is below a threshold and the interior temperature difference is too big and otherwise, the heatpump operates. By comparison, my house is two stories + basement and about 1600sqft.
Now the issue we have is that the smart thermostat wants to inform me when the furnace runs for too long.
11:08 Missed opportunity to say miles instead of kWh when describing the total kWh consumption of heating your home in the test. Obviously this is a real strech of units, but I'm people say "we dont have enough capacity for everyone to have electric cars" but easily have 110kWh to heat with resistive heat. Thats enough juice to drive 3-400 miles.
Great video as always!
We have a 28kW combi boiler which is way oversized for heating. From what I can tell, on the coldest days we have, I use about 120kWh gas. Optimistically at 80% efficiency, that's 96kWh heat, or 4kW running continuously. Replacing that with a 5kW heat pump and hot water tank soon hopefully
This is fantastic, Alec. Preach! When we were sizing for a geothermal heat pump here in Central Illinois there was definitely a push to oversize for a home that has (insulated concrete foam) walls rated at R-25 running to the roof. Even with drilling wells, that entire system was WAY less than the $20k wacko quote you cited.
Do you have recommendations for smart thermostats which are NOT tied into a big data company like Google? We want to track that data inside our own network, and don't want to be reliant on a third party that probably has a privacy policy worthy of one of your loving 30-minute shame fests.
Ecobee can be local, in my understanding.
But there are many options. Key words for internet searches would be things like "local only control". I recommend engaging with the Home Assistant community as well; zero-cloud smart homes are a big focus for most of us.
I had to get 22 estimates to replace my oil furnace with a heat pump because all but two of the estimates were predatory, in exactly the way you describe. They tried to sell me heat pumps that were 3x bigger than I needed PLUS a gas furnance to supplement it! Estimates were: 1 @ $12,000, 1 @ $15,000, 17 @ $22,000-28,000, and 1 @ $42,000 (this snake said my house needed 2 6-ton heat pumps). Also, the heat pump I got ($12,00 estimate) is waaaay more energy efficient than the ones quoted to me that were 3x the size I need. And, just like you say, the oversize units would have required me to replace my electric panel. Just like you describe, my central duct system doesn't have the capacity to handle the giant heat pumps they were trying to sell me, but its the right capacity for the appropriately sized system I bought.
I thought I was going crazy when I was getting all of these estimates, so I called the state Department of Environmental Quality to ask what capacity heat pump I needed for my home and they confirmed these $20k+ estimates were insane. They were totally clueless that companies are giving estimates like this. I also used the J Manual calculator and it confirmed the size heat pump I need.
When I said no to these wild estimates, and expressed disappointment that the units they were trying to sell me had such low energy efficiency ratings, then they tried to sell me ductless mini splits, even though I have a central duct system and mini splits would do violence to the architecture of my 1890 Craftsman home.
I also have a bee in my bonnet that they all told me I had to have heat strips. I looked into heat strips. They are the energy equivalent of using space heaters in every single room in my house, which is wildly energy ineffecient. I said no to heat strips and on the 0-2 days a year the weather is much colder than normal for my climate, I use a space heater in each of the 2-3 rooms we actually use at the same time.
In Europe the "combi boiler" is a common thing for hydraulic heating and warm tap water.
The tap water means that these are severely over specified. But, they do allow power control over a good range, for example 6 to 24 kW. How low the low end is gets more attention in recent years.
I've capped mine to its minimum setting.
As we turn to secondary heat sources and heat pumps, contractors will feel less need to overshoot the requirements as they did with typical gas furnaces. You design for what you currently have available, not for what MAY come in the future. People don't want to freeze their butts off now just because they MAY be able to afford an upgrade later. But you are correct in that most contractors rarely do their manual J beyond the initial install.
I used to work with people who sold heating and plumbing units. The manager would just ask "Whats the square footage, what's in there now, how many floors", do four lines of napkin math, and point them at a unit. They only ever downsized if the customer stressed "It's *brand new* construction."
It barely got under 32*f here a few times this winter. My Gas Furnace is from 1975, I'm scared to run it, its a 80,000 BTU unit for a 1400SF house... it heats me fast. But power is cheap for me (9c/kwh at night) so I plugged in a space heater, set it on level 1 (600W) in october. I am here in november, and my main gas heater has only clicked on a few times all winter. IMHO amazed a single space heater kept me warm all winter.