How Much Energy Does MrCool Heat Pump Really Use In Winter
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- เผยแพร่เมื่อ 28 ก.ย. 2024
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I installed a MrCool 36,000 BTU Universal Hyper Heat ducted system last summer and just ran a test measuring the energy consumption in temps down to -9F. This unit actually can maintain a 71F thermostat setting in these extremely cold temps but at what cost to total energy consumption? I will share my results so you can make an informed decision for your own home or project.
DISCLAIMER: This video and description contain affiliate links, which means that if you click on one of the product links, I’ll receive a small commission.
Technology Connections did a great breakdown where he put these "brutal" cold days in context of when they happen and the frequency, which isn't as much as people believe they happen. It's ideal to have some backup, but even on these brutal days which last not that frequently, you can plan ahead and heat extra during the day when it is sometimes warmer or use an extra heat source. Also, heat pumps are getting even more efficient for colder climates, all the way down to -20c (-4 f) before they loose efficiency)
Yes he did a great job, and always does. This video is missing something like the house is very inefficient so the heat pump is performing poorly due to that.
I have a MR COOL 2/3 ton unit. At the moment its set to 2 ton. The most I've seen it pulls is 5.041 KW. I was very suprised it pulled so much. Im having it switched over to 3 ton when I get back home next week because its having a lot of trouble keeping the house warm at 2 ton, in a 1440 sf home. Also on most energy company apps, when you are on the daily chart, you can click on "see details" and it will break down the day by the hour. Great video.
Technology Connections has a great review of the trade-offs.
In short, even if heat pumps are--in very rare circumstances--less energy-efficient than gas or electric, they are still VASTLY more efficient over the heating season.
That’s why dual fuel systems are the ideal solution!
While they are more efficient, when I did the math on our home, whether we got multiple mini splits or central ducted with our existing ducting, the cost for the install/units/electrical versus oil costs/season meant there were no realized savings until the units were far outside of the warrantee period.
Agreed. "Below 30 degrees is not a "rare circumstance" in the Northern US@@bpdp379
Next home upgrade - better insulation !
Not knowing your insulation situation, you have oversized your unit by 50%. In a very well insulated home a 2 ton unit should be sufficient.
Not that an oversized unit is terrible in the heating months but in the summer it would cool the house so fast that you would loose the ability to remove humidity effectively.
Then again maybe you don’t have a humidity problem like we do here in Texas !😅
It definitely gets unpleasantly humid in IL in the summer. Sure, not as bad as Houston or Baton Rouge (most days) but still uncomfortable.
Thank you for the energy usage breakdown! Most videos just focus on whether or not the heat pump works when it gets below 0F outside, which current technology clearly handles. But the reality is that the COP does decline with outside temperature, and there is a point where something like natural gas can made sense economically if your outdoor temperatures are below that point. .
First of all, great video and installation, everything was clear, and workmanship looks amazing. I had a couple of comments for a deeper dive, heat pump performance is sensitive to system design and what you experience will not apply across the board equally. 1) If you can better estimate your home's heat loss based on prior fuel bills or a heat loss calculation, that will go a long way to getting better insight. You mentioned your home's insulation levels but air leakage can be an even bigger variable, especially on very cold days. 2) The other side of the equation is the heat pump efficiency. Some models are better than others, but in general the efficiency is strongly dependent on the difference between the outdoor temperature and the heat pump condensing temperature (how hot the refrigerant is in your air handler coil). If you can deliver the heat into your home with a lower condensing temperature, your bills with a heat pump will be lower. For this reason, distribution system design has a big impact. In general, if you can move more air at a lower temperature, that is more efficient than moving less air at a higher temperature even if delivered BTU are equal. Since your duct design was reused from a high temperature oil boiler, it may be undersized for the best possible performance of a heat pump. Measuring your blowers air flow, static pressure, and heat pump condensing temperature would tell you where those things stand and if there is room for improvement. Maybe resizing your duct work is not practical, maybe there are some things you can do, but without measuring, we really don't know. Heat pumps are amazing, but system design is more complicated than high temp combustion furnaces unfortunately. For comparison, I have a 2000 sq ft house and it consumes roughly 25kWh (from heat pump) on days with a ~34F average temperature which is less than your system for twice the square footage.
My 36,000 BTU Mr. Cool unit heating my workshop used 80 Kilowatt-hours on my coldest day with a low of -6 and high of 4. Crazy amount of energy usage. I just installed some propane heaters for these below freezing times.
I need to get my detached garage insulated so I have a hope of heating and cooling it. I dream of the day with a huge workshop on in-floor heat 👍
What’s your cost per KWh for electricity? Where is live that would be $4.40 worth of electricity (5.5 cents/kWh submetered winter heating). That is the same cost as 2.5 gal of propane in my area ($1.70 per gal summer fill)
@dustinsnyder3483 my electricity is $0.15 per kwhour.
Awesome video, so great to see numbers. We are off grid in Alaska powered by solar and just installed a one ton Mitsubishi Hyper Heat this last fall (everything installed except the line set). So we'll have it connected in the Spring fingers crossed. Very interested in how much power it's going to require!
Our numbers for our 1200 square foot cabin are:
Floor insulation: R-53.7
Wall/door insulation: R-24.0
Ceiling: R-59.4
Windows: U-0.26
Window SHGC: .21
Window to Wall Ratio: 12.3%
Air leakage: 1.05 Air Changes Per Hour at 50 Pascals
Heating Design Load: 11,964 BTU/hr
With you using 40KW around freezing and 120KW at -5F, we're really hoping our extra insulation and smaller heat pump will bring that energy usage down! In the darkest month of the winter we'll be lucky to bring in 20KW of power with our solar on a good day (but outside of December our production goes way up). But we'll have a diesel DC generator as a backup, so even without sun we can either use diesel or use the wood stove.
Eagerly awaiting the performance of our heat pump next winter... Thanks for sharing your numbers, great video!
Nice work on the R-values 🙌 I think you will do much better but at the temps below 20F it would most likely be wise to have a supplement the need for heat with some type of fuel source. Wood burning stove or pellet stove would probably help to cut off the crazy ramp in energy consumption.
@@everydaysolar absolutely. We have a wood stove for heat now. We've been at this for just over five years now and this past summer we added a ton more insulation since our walls were still not closed up yet. This summer we hope to install the floor and start on interior walls and counter tops and such. Every inch out here feels like a mile. But we could tell the insulation did wonders because we now hear an echo inside the cabin and because the stove burns so much less wood. We were thinking about getting a Webasto diesel heater too, but decided instead to use diesel to charge the batteries to run the heat pump since that would burn less diesel to heat the cabin due to the COP even during the cold temps.
We've got a 3 ton Byant heat pump in our 1800 square foot house down here in Texas. At the same time you were getting your -5 degree temperatures, we were getting +5 degree temperatures. In general, outside of those days, in winter, our heat pump also uses around 25-30kWhs per day. On our coldest day (again, about +5 degrees F), it used 217kWhs. So, we pretty much match.
We are in Canada and had a Dettson central heat pump installed this past fall, configured in dual fuel mode with our 96% efficient gas furnace. We have it fall over to the furnace at -5C or colder as gas is cheaper to burn at that point. That said, we accidently ran the heat pump at -16C or so and our total kWh for that day was under 60 kWh for the entire house, not just the heat pump. Another important factor in this is how well air sealed and insulated the home is; as the air from heat pumps is not as hot as from a furnace, it takes longer to heat the home and especially leaky homes may lose heat faster than the HP can keep up. Our home is ~80 years old but we've gone to great lengths to air seal it. I also noticed that heat pumps are more comfortable as they run much longer than a furnace with cooler air (furnaces simply blast hot air to satisfy the thermostat as fast as possible and then shut off).
At this rate, the heatpump becomes a false economy. It's better to stick to propane heating. The colder outside conditions the worse the COP factor. They only do well heating water.
@@eugenehowat4505 they're great in mild climates like the PNW for old people who refuse to turn down the thermostat and thus do a lot of heating from 40 to 75ish
Need a solid backup for the cold snaps though.
How is the humidity levels inside the home with the heat pump? That's one thing I've noticed when we run our furnace a lot is that it is insanely dry in our house, like 25 percent humidity, even with a whole house humidier.
@Eric-ii9ce well I guess I'm not doing too bad then all things considered. I was kind of hoping heat pumps kept the in house humidity a little higher.
@Eric-ii9ce ahh fair. I'm in nothern chicago and our outside humidity is generally pretty high in the winter (almost always above 60 and generally 90s for a lot of the winter).
Wow, that consumption on the cold days is nuts. Very eye opening. My model Y uses about 350 kwh driving it for an entire month. At least it's able to heat in below 0 temperatures.
Have you looked into heat pump clothes dryers? GE makes a compelling model that use a lot less energy than an electric ducted dryer.
I haven't looked at the clothes dryers yet but I am eyeing a comparison between a standard electric water heater and a heat pump unit. Would be interested to see the difference in power consumption.
@@everydaysolar If you have a space that can maintain >50F the heat pump water heater works quite well. They do make a little more noise, more like a buzzing noise, also. Mine was installed in may 2021. Annual usage has been: 571kwh (7 months) / 1094kwh / 1257 kwh with 2A, 1C household. I would say the biggest change in the last 2 years, has been more frequent baths/showers for the kid. I'm not sure how much I was using before the change, but I do recall immediately seeing a significant drop in usage after it was installed. We also had a change in washing machine in late 2022, from a front load HE machine to a top load less efficient machine.
There is no comparison. My 50 gallon rheem used 870 kilowatts last year. A straight electric one would have been 3-4x that number. @@everydaysolar
Our carrier Mini-split can go to -22f but very little heat is moved at that temp. It's ok down to about -5f. We supplement with a pellet stove and the old electric baseboard in the bedrooms. Over the year the bills are pretty decent.
I’m planning a renovation using a carrier mini split as my primary heating source in NY. I’m trying to figure out if carrier has a graph showing at what temp the efficiency declines at a given load. The mfr’s are cute saying they can maintain 100% heating capacity down to -22F but obviously at a tremendous cost. Would you say your carrier is still very efficient at 15F?
@@greg03811 yes, the COP scale is right in the manual as I recall. Pull it off their website. Mine does fine at 15degF and we are in SE MN.
Very good high level presentation! Absolutely true conclusion(s) for realistic cold climate installs. (Key words: realistic, cold climate.) Signed: test engineer with ductless heat pump system installed in my MA home.
Thanks for sharing this data, looking forward to seeing the summer numbers.
You bet!
I installed a Tosot 12K mini split into a 10 X 16 Greenhouse, all insulated except for the 45 degree slanted roof solar windows, single pane, total exposed, 8' X 12' area. It was installed mostly to allow my freeze sensitive plants (citrus) to winter through the North Texas cold spells, seldom going below zero, but always at least once a year, for a few days in the singles and teens. Had such an event last week, ran it at 61, the lowest it would go, but with Turbo fan to insure no cold corners, and was surprised to see it was handling 7 degrees outside and 61-62 inside. Also, the Condenser was running about a 35 to 50 percent duty cycle, which was even more surprising. It is a 240V unit and did not seem to be working very hard at all, but I am curious what the power draw was on that unit alone. I'll have a better idea once the bill comes around as I normally have an 80 to 120 buck bill in the winter (Gas Heat in the house), and we'll see the change when it shows.
As far as I can tell, those heatpumps are still using R410A Refrigerant? That's being phased out completely here in Europe for a while now, all replaced with R32, which in turn is now being replaced with R290 - much better performance in cold weather compared to R32 - and R32 is already much more efficient than R410A.
I see lot of heat pumps these days being rated for up to -25C, i wonder what is the performance in the -7 to -15C. In the area where i live there are like 7days when it reaches that temperature during the night, most of the time is 5 to 8C high and 0 to -5C low. My parents have 2 with R32, but never use them in the winter.
@@ristekostadinov2820 Heat pumps in general are huge here in Finland, which regularly experiences temperatures like yours for extended periods of time. The main type used to be ground source, but with improved air source heat pumps and refrigerants, air source heat pumps are extremely popular. Based on the discussions I follow online (especially now that we have the coldest winter in 20 years) they seem to work fine for most people.
That sounds about right. They work great in milder weather, but not in very cold weather. A wood stove isn't a very expensive backup option. My stove is my primary source with baseboard heaters as backup.
I installed a 60k Mr Cool Hyper Heat Pump and notice that the overall cost to heat my home this winter is already significantly higher than my previous 65% efficient 1989 gas furnace it replaced. This comparison is limited in that it is only for the past two years, through the relatively warm December this past year. If I remember correctly, early winter last year was a bit cooler (or at least we had more snow). I am not sure I would recommend the heat pump for Michigan winters yet, at least not until the utility provides some sort of reduced rate for heat pump electricity. I would be interested to know what the financial breakeven point is for installing a heat pump vs a more traditional gas furnace. I know there are a lot of variables, but I think a thorough analysis would be helpful for many making this consideration. Thanks for the videos!
You would need to factor in the cost of gas that you saved not having a gas furnace anymore. Of course, you will use way more electricity by heating with electricity than heating with gas but that doesn't tell the whole story. However, I think everyone knows that typically gas heating is still cheaper than electric heat pumps. If your electricity comes from solar panels then heat pumps can be cheaper.
HVAC business here. Totally off grid going on two years. 32kWp, 168kWh LFP. 3.5 tons of 16 and 20 seer HP’s on house, Fujitsu 9k 33 Seer on power shed. All electric home, 1960 sq ft. I made it until 1/2/24, then had to light the wood burner. I would recommend running most heat pumps down to 10-20F, depending on COP and HSPF of hp, then switch to gas/wood/oil. I still run blowers at times to circulate heat better.
I have a 2000 sq ft home (heated space) that is heated by a gas furnace/ and cooled with a air conditioner. The garage has a Mr Cool DIY mini split 24K unit for 1000 sq ft. This is my first winter using this unit. It keeps the 3 car garage heated at 65 degrees using about 6KW hours per day, and peak power use when the temps were in the teens at 17KW hours when it never got above freezing. I'm very happy with the Mr Cool mini split.
Dang, that is not bad at all. Assuming you have at least a reasonable amount of insulation in the garage?
Second year heating with a 4/5 Universal set at 4 ton heating 1400 sqft in central Wisconsin. Last year had -18 and this year -11. No issues keeping warm. I am all electric and my last bill was $120. I don't have the breakdown for that but that is for everything.
For the author of this video if you are in ComEd territory go on the real time pricing program. My other home is in Illinois using a geothermal heat pump. The real time pricing has saved me thousands over the last fifteen years.
I am also in central WI. Did you replace a natural gas/or LP unit? If so how does it compare.
My heat pump spent more time in "Defrost" mode (where it runs but isolates the air handlers to de-ice the outdoor coils) than heating the living space!
I use my 98% efficient gas furnace in winter and the heat pump the rest of the year.
Really enjoyed this video! Thanks! I just (like 2 days ago) installed the same 3 ton system in my house. Looking forward to your update video when cooling vs heat.
It's really convenient to compare against gas but in my area I don't have gas available so I have to compare it to propane and my split system is greatly cheaper than my previous system and I was surprised when it got to minus five and my units kept us comfortable, I couldn't be happier with my new units!
Im not keen on putting outdoor units direct on the base especially in colder climates as the regular defrosting promotes ice build up as it runs off.
Really the outdoor should have a minimum of one foot clear space below it to clear the water. It also helps to get the cold air away and promotes better air flow circulation
Mr cool should not be used in cold climate heat situations. This was the issue with early heat pumps. Mr. cools are only full heat rated down to 17 degrees. Where as cold climate heat pumps today are rated output down to -5 to -15 F.
I’m running 3.5 Tons of 16 and 20 SEER central hp systems. I was doing fine above 30F. Below that or more three cloudy days and the wood burner got lit 1/2/24…and I have 32kWp, 168kWh LFP! My 80 gal hwh consumes 15-20 kWh and total for my all electric home is 50-80kWh per day. I’m going to build a heat pump water heater for next winter.
Maybe another topic for another day, If the air handling unit can be located in a conditioned space in the house, and the ducting well insulated (and/or buried in blown-in insulation) it may be possible to get a smaller unit that accomplishes the same heating and cooling as a larger one. I was able to do this while doing an energy upgrade remodel. By reducing air leakage and increasing insulation in the attic, exterior walls and crawlspace. I was able to downsize the new design from 3 to 2 tons. This will save me money on energy costs for heating and cooling as long as we own our home. Possible savings are dependent on your starting point, construction type and the relative ease or difficulty of air sealing and insulating your building envelop, choice of equipment (with attention to life-cycle location of equipment and ducting.
two questions: 1. Why haven't you taped up your ductwork seams with foil tape? 2. If you live in an area where it gets to -5, why didn't you opt for the heater kit? The power usage might have been less if the heater coils would just need to kick in for a short while to get the living space up to temp, and then the heat pump could work to try and maintain that temp.
I need to seal up the duct work but wasn't too concerned as I actually wanted a bit of heat for the basement. I didn't get the additional heat kit because I wanted to see what the heat pump could do in this exact instance so I could record the data and share it with the viewers. If I was just installing in my house without taking data I would probably have went with the 5kW heat kit for a little backup in the brutally cold days.
after -15c There is no comparrison to wood heat for effiency and carbon footprint. It just works!
In Alberta, Canada, -30c our power grid is under alert as we do not have enough power. 30-50KW in one day is just mental at $0.28/kwh you would spend $14 to barley heat your home. Or you could spend $6 on a bag of pellets.
Thanks for including your rate it helps to see the range of rates across the US and Canada. We are lucky in my area to have a flat rate of $0.08 / kWh.
That 36,000 BTU spec caught my eye (see below, for pointless anecdote.)
Energy consumption only has relevance over time, never on any one month's bills! Scott, your other video about its ability to maintain 70 in below-average outside temps is all that matters ... because it seldom reaches that cold in Illinois or stays very long.
And since the "emergency heat" option wasn't needed, neither would other supplemental heat be helpful UNLESS that other alternative is known to have lower costs than running the compressors 24/7 (all else being equal, but it never is with wood, gas or oil.)
That is why, "being off the grid" is romance, not practical for homeowners and not helpful to *neighbors* who have to shoulder infrastructure costs the "off grid" citizen does not contribute to. Another hat tip to Alec at Technology Connections for mentioning the un-obvious.
Fun fact: I once heated most of a 1600 sq ft house with one small, 36,000 BTU ventless gas stove in the basement, the kind that sell for less than $500 and look like an old fashioned wood stove. The basement (800 sq ft) was too warm and the upstairs could get cold, but we made it through for a year like that. But the IAQ did suck, to say nothing of depending on a gas pipeline.
Those numbers are horrible for a house that small, I have a mrcool universal and it’s set to 2 ton by dip switch’s but can do 3 ton aswell, can yours do the same? My best guess is you would half those numbers if you can switch it and air seal and add more insulation, I also have a blueridge 38 seer 9000 btu mini split in my living room that will heat my whole 1500 sq home to 72 the lowest temp so far we have had for that is 36 outdoor temp, I use that one all day except at night when all the bedroom doors are closed then i switch to the mrcool ducted.
I was seeing power numbers like that during the same cold spell, except my air handler draws less. My heating and cooling seems more even than it was with gas, conventional AC and single speed blower. It might allow me to get away with a lower temp on the thermostat. We had a bit of snow with our cold, just enough to wipe out solar, so all we'd need to go off-grid is an entire basement of batteries. :)
Very good video. Do you have stats that show the cycle times for the condenser? Curious to see how often it is turning on, ramping up and then turning off.
i watched your other video where you showed the heat pump putting out 90+ degrees at the floor register on a super cold day - my new carrier seer 16 heat pump is only putting out 70+ heat on a day with temps in the mid 20s!
Hmmm, do you know what they claim for the lowest operating temp? The Mr Cool Hyper Heat I think calls out -26F.
What was your indoor temperature? If it was 50° in the house, then that makes sense. Most standard 10 through 14 seer central heat pump systems will put out anywhere from 80 to 95° supply temperature without the electric resistance heat energized, depending on the outdoor temperature, of course. Most mini split heat pumps between 18 and 33 seer will put out 100 to 124°F supply air temperature.
Most likely, because the system is oversized for a 1000 sq ft home. Unless his home is poorly insulated.....
We have a 2 ton air heat pump system on a 1400sqft home that is 16 years old. During the cold snap with a high of 3F, we used almost 200kWh. Sounds like this system isn’t much more efficient in low temperatures.
EXCELLENT video! I wonder what effect on total energy consumption heater strips would make? My system has them and switches over automatically. I don't have natural gas or propane at my house so all electric is my only option.
heat pump is the future. Great video!
What is the cost comparison to the oil or gas and entire home electric/heat combined vs going all heat pump? I want to know if is worth switching to the heat pump and the main reason to switch if your total cost was lower. I have too many neighboring trees to get solar to offset.
I know you are testing the concept. So in future videos, your net cost would be interesting to see compared to what you were using prior to switching to heat pump would be interesting to see since you are tracking. It's less important if you're using a lot of electric on super cold days. If overall, it averages out to using less energy or a less expensive energy over the season. But you didn't address that yet.
I would be interested in seeing if a radiant floor system such as “Warm Board Radiant Floor” that does offer a heat pump as one heating source vs the forced air system that you are using, would be any more efficient.
Both your wall and ceiling insulation are only 1/3rd of the recommended levels. In a northern climate zone, your walls should be R40 with at least half of it continuous insulation as opposed to cavity insulation between studs. Your ceiling/roof insulation should be R60 with at least half as continuous on the exterior. There is a 4000sf Passiv house in Canada that uses only 1500w average winter load on its heat pump, because it was properly insulated. Your insulation levels might be "typical" for a lot of older homes, but I don't think it is rational to expect an inefficient home to get some sort of miracle out of even a COP5 heat pump. Also, have you had a blower door test to see how badly the home leaks ?
Due to the thermal inertia of the buidling one should expect a higher energy consumption in the case of longer lasting cold temperatures.
💯
Still planning on doing a summer power draw update running AC mode ?
I have never heard a recommendation for Mr. Cool in a low temp area (other than from Mr. Cool), there are makes/models that are better for sub -0F performance.
Those other brands/models are just heat pumps or a hybrid system?
Thanks for calculating this information. I Highly recommend our government see your video and stop trying to end all other sources of energy for home heat / cooking. Green is not very warm.
Is this the mr. Cool hyper heat centeal ducted or the mr. Cool universal
Here in Charlotte NC where it is not too cold, we use the heat pump for most of the load, firewood in an enclosed fireplace to supplement during temps below 35 degrees ( 15 days a year ) . We do have electric strip heaters within the heat pump for back up, but I have the breaker off and only use them for extended cold. ( maybe one day per year ) Here is a question for you, if you trick the outdoor unit to think it is warmer out would that improve your efficiency, such as use the heat from the firewood pushed into and around the outdoor unit coil ?
the solution is to do dual fuel - nat gas and propane furnace combined with heatpump, in the cold snaps switch to gas
Not true - they do work in winter in canada - the cold climate models give full capacity below 0F. Even the conventional models can work at pretty cold temps but don't give enough heat. Most of canada where there's population is usually not that cold - even the parts that drop to -40 have a lot of days during heating season that a heatpump works decently.
The new tech has really been a game-changer for heatpumps in cold climates
The cost of a heatpump not much more than the equivalent a/c unless contractor is gouging, in which case find another contractor.@Eric-ii9ce
Hello sir, thanks so much for the great videos.
I have 1 question how does this unit do for dehumidification in the summer ?
It’s not JUST the unit needing more power when it’s colder, but your home needs more heat when it’s -5F versus 34F due to a larger delta.
Agreed 👍
can you compare setting your tstat lower during the night vs keeping the temperature constant
Yeah, that would be a nice test. I will see if we get another cold snap. I wanted to push the unit a bit for this test but setting the termostat to 65F would have gone a long way.
Seems a bit odd that this heat pump requires a 50 amp breaker for a 3 ton unit . Normally it would require a 30 amp circuit breaker which could point to higher energy usage .
Yeah, heat pumps are only really efficient above freezing. They make it nice for the shoulder seasons, so you don't have to keep a fire going, but for anything colder than freezing we use wood.
Even on his coldest day that's $6 of electricity where I live. I'd say it's worth it.
@@Egleu1 His highest usage was 115kwh per day. Even at 13 cents per kwh that's 15 bucks a day. Gas is way cheaper than that.
@@spuriouseffect sure but I pay under 5 cents so it's a viable option. Gas is currently 57 cents a therm, I'd have to calculate it out but you're probably still right that gas is cheaper.
On your coldest days you are getting a COP of about 2.0, meaning for every kWh of heat you are only using 0.5 kWh of energy. If you used backup resistive “heat kit” heat coils like you mentioned early in the video, your unit would draw up to twice that energy on your coldest days. Anyone who sees this video and decides to use heat coils because you don’t really warn of how horribly inefficient they are compared to hyper-heat, those people will likely be very disappointed.
Make a doghouse for the condenser that uses a Chinese diesel heater to increase the temperature inside the doghouse.
I wonder how much power a geothermal heat pump system would use in this same situation???
I bet your loving your solar when you see those figures.....imagine the bill without it!
I aint producing that much Solar on this property 😕
Not sure where you're located, but R18 in the attic? Seems like a change there would make a big difference.
Yeah, it would be nice to up the insulation but unfortunately it is a flat roof and no attic space.
I have a 3 ton hp by Amana and I'm curious why the me cool is less efficient. My hp on a 40 degree day or even 30 degree day never used more than 30 kwh.
How often do you need to run the auxiliary heat if your lows are in the 20-30F range? We are heat now and love the warm temps. Decades ago, we had a heat pump and had to run our auxiliary electric quite often and that added greatly to the bill. Hopefully the heat pumps are more efficient now.
This unit doesn't have the additional heat kit but that is an option. For these results all of the heating was just from the heat pump. The tech has come a long way but when temps get below 20F it would be nice to have an alternative heat source like propane or natural gas to lessen the energy consumption.
Try calculating btus created at 30f and again at 0f. BTU Output = Air Handler Temperature Rise (Д T) x CFM × 1.08. In your previous video (based on 0f) it would have been btu = 20f x 1320cfm x 1.08 = 28,512 Btu/hr. However measuring temp rise (delta T) at the air handler is the correct method, not at the register.
By the way, 7 kw of power at -9f IF used by electric strips alone calculates as kw x 3.412 or 7,000 x 3.412 = 23,884 btus.
What people don’t realize is low ambient “hyper heat” heat pumps actually increase compressor rpms at low temps increasing btu capacity by 20% or more. Which effectively makes a 3 ton unit 3.6 to 4 tons but only when using the “hyper overspeed capacity” at low temps when heat pumps normally drop their output btus fast. The “hyper” overspeed ability increases power consumption and noise much more than you would expect because of other complexities in the design which require extra refrigerant cooling circuits to the body of the compressor and a special hot gas bypass defrost circuit for the condenser. The complexity typically requires two electronic stepper motor txvs in the condenser, a solenoid and a special “dx” heat exchanger for the extra compressor cooling circuit. While all of this has been proven in residential by Mitsubishi over the last twenty years, other brands reliability with this complexity is an unknown. So good labor/parts warranties from the manufacturers, ideally ten years or better, is worth investigation. On the plus side, all of these low ambient designs require variable speed compressors which is great for low power and noise in normal above freezing heat and cooling modes.
Awesome video. Great data.
Thanks for the feedback!
Wouldn't a ground source heat pump have performed better? Where can I go to see a air source to ground source comparison?
I think it would do a lot better but the initial install cost will be a multiple over what I paid for this DIY unit.
So, do these systems not need to run in defrost mode ever? No supplemental heat means you are cooling your living space while the unit defrosts???
Yes, when the outside conditions drop like during the test the condenser will need to run defrost cycles. Usually that just means your home will not be heating during this cycle.
@@everydaysolar so do they defrost differently than a normal split system? Most systems run in AC mode during the defrost cycle.. What exactly do the Mr Cool units do? Do they have heaters on the outdoor unit themselves then? Something is accounting for that massive spike in energy usage..
@@stevenlilly I think the cycle is the same as a traditional mini-split system but the air handler will not run so you won't be pushing cold air through the ducts.
what would it cost me in electricity with the average cost of electricity, if the temperature stays between 20 and 40 all winter
What is the rate you are paying per kWh? We pay a flat $0.08 per kWh but this can fluctuate across the US and in some areas even fluctuates different rates throughout the day.
Yea on that -9 degree day you were most likely under a COP of 1. This would mean that if you had them it would have been actually cheaper to run the resistive backup heat over the heat pump. I know on my three ton ducted hyper heat unit from a different company that has COP data published it goes under a COP of 1 at -4F.
Yeah, I think you are right. There is a crossover point where running the heat kit would have made more sense. Thanks for the feedback 👍
Wow that is not too great, my Water furnace heat pump using my well water does a whole lot better than that and I have colder weather than you about the same size house but better insulated and I have never hit 1200 kwh for heat in a month usually 800 - 1000 kwh for most winter months. It has always done the job and never used the 8000 watt resistance element unless it has to catch up from being shut off. Thanks for the information.
Thanks so much. I guess that I was totally confused in that heat pumps saved energy. I almost went that route.
This unit does a good job and honestly pretty reasonable on the energy consumption until you get 20F or below. Then it kind of falls of a cliff for efficiency.
Heat pumps are only more efficient than a electric heat unit until you need the electric heat to kick in. Overall in the winter below 20*F a gas furnace will beat it everytime.
I still haven't figured out why our Government is trying to do away with gas knowing darn well that the power grids are maxed out during freezing spells.
You should have gone with a mini split . You can have 30% losses using a duct type unit. Having a head in each room will let you control the temperature in each room. You need warm window brand window coverings. You need passive solar glass on the south side of the house.
If you are going solar you first need to cut losses in the house.
Heat pumps for heat makes no sense when authorities are trying to phase out gas and rely on solar power. You end up paying a fortune to your electric utility unless you double the size of your solar array generating surplus power in the summer and TRUST that your electric utility will credit you fairly, which they won’t.
Your air filter needed to go on the right hand side of your plenum stand and plenum stand needs to be taller.
Really, would you just fabricate a taller custom stand/plenum?
@@everydaysolaryes, I use 26 ga sheet metal and a 4’ brake. You don’t want the air coming down the return drop, then hitting the flat side of the air cleaner. We typically make that elbow flow straight into air cleaner then into matching height plenum stand.
I will continue to burn fuel and wood for my heat.
doesnt that ACTUALLY depend on the weather AND how well a building is insulated? so pretty much anything in this video is speculative SMH
For sure, but that is why I included the temperature and R-value of this home. That should help you relate these findings to your own home/situation. Were you looking for something else?
@@everydaysolaryou’re amazing - so detailed and thorough. I don’t know how you do it and still have time to sleep. 😅
This is why I want a ground source heat pump. You're basically always in the most efficient zone of the heat pump regardless of the outside air temperature. This just reinforces it. Just because these new air source heat pumps CAN work well below freezing doesn't mean you should or it's efficient.
Very true. I love the idea of a vertical or horizontal ground loop but the cost can be pretty steep. Have you already priced out what you are looking at for your home?
@@everydaysolar Yeah as a retrofit it's pretty crazy. I'm planning on doing it as part of new construction, so the equipment will already be there digging the foundation/etc to dig the horizontal loops in. Combined with the additional rebates and tax incentives, it's much less of a jump. Anyway, air source still saves tons of money in the 25-60F temp zone. I love my current one even if I am running heat strips now. haha
I agree the ground source pumps are the best option, however, we all don't buy a house or land with the knowledge of the type of soil and underground utilities in the area. If my house is on ledge and there's no viable location to put in a ground loop, then the air source pumps are a relevant alternative.
You’re doing great for a DIY’er. Thanks for sharing on yt. My Fujitsu 9000 BTU 33 SEER consumes about 1920W at 100%, so four of mine would be about equal your 36000 BTU. Similar power consumption per ton.
These numbers seem pretty high, which probably indicates that your heat loss is a bit higher
In second week of January we had similar temps in Europe (-7C low/0C high) and my 14kw heat pump was using up to 50kwh per day, but for a 185 sqm house.
Have in mind, my heat insulation is better, but my windows are 20 year old wooden double glazed.
We worry too much about heat pump efficiency, but in the end, if your heat loss is high, heat pump needs to use a lot of power to compensate.
Yes, very good bottom line point on heat pumps and heat loss. Efficiency is a double edged term in this case. Efficiency: 1 (manufacturer choice use) - does the system provide heat/cooling in all conditions, 2 (operating cost) - energy consumed and operating cost. Manufacturers aren't always as clear as they ought to be about efficiency. Operating cost is also connected to electricity unit cost in your area. MA has highest national cost per unit of electrical energy (except for Hawaii). In my case, i am forced to use pellet stoves for heating and the heat pumps for AC. Be very careful, Scott's graph temp. vs electrical consumption is spot on.
Very important for potential conversions to heat pumps: 1. have an accurate heat loss (manual J) assessment done by very reliable professional, 2. If heat pump(s) is/are still a good option, select very reliable heat pump/home system professionals. I found this is a very difficult effort. There are very few reliable professionals in this field, 3. Have the professionals go over the project in detail and make certain you understand those details. Don't go with 'trust us, you will be very happy with the system and the savings'. 4. Select the best system on the market, emphasis - do your homeowrk.
If 50A circuits have to be added to run the system, this is a huge flag that a lot of electricity will be used to operate and lots of $$$$ for that electricity.
Don't be fooled!
I thought the same thing . Usually a 3 ton heat pump requires only a 30 amp breaker
If that’s the quality of insulation on the primaries, god help you.
Only rich people can afford this 😢
I would think the Mr Cool is an option for most people to save money. For my installation compared to pro installed I saved close to $7,500 🤷♂️
So would the auxiliary resistance heaters actually prove to be more efficient past a certain temperature? I’d love to see that data.
I think that would be true. Just a guess but around 5F or 0F with this setup the supplemental heat strips would probably be more efficient than the heat pump.
@@everydaysolarI’ve been fully off grid the last 3 years with a fully functioning house and have never needed to start a generator once but that’s with propane furnace, stove and water heater. 5kw of solar, 30kwh of lfp. I’m starting to plan for the next build and would like to go fully electric but the main problem is heat. I live at 8000’ in Colorado and I experience consistent night time temps below 0 for a few months each year. I feel like if I have any hope of achieving 100% electric everything I’ll need to go with as much insulation as I can and make it as air tight as possible. One option I’m thinking is going with in slab radiant heat with a electric boiler as I’d be able to dump heat energy into that during the day and then use that as a thermal battery of sorts to get through the nights.
It would be more of an apples to apples comparison if you converted the gas used to BTU's and for the same period convert the Kwh to BTU's or for equal time at various temperatures with both systems. More for those on grid looking to see which is more cost effective. I know oil where I live is over $4.00/gal while a kwh is about $.14. I have been running mini-splits in my shop, (14000 cu ft), home (8000 cu ft) up and 8000 cu. ft. down. for four to five years. When it gets below the mid twenties F I notice it is spending a lot of time defrosting itself (very inefficient). Which brings up a problem with modern mini-splits, how to know when they are running at top efficiency and how to know when they are not. Older systems just required a gauge applied to see if coolant was up to snuff where as a mini-split requires a full pulldown of the system and weighing the charge. A process not everyone is equipted to do (I have all the equipment and even so it is a job I put off when I am not sure it is needed). The insulation that comes on the linesets are only minimally insulated (the R value of that foam jacket is around R5) and because they are installed back to back the efficiency of that delivery system is degrading the systems considerably. You just can not run a hot line immediately adjacent to a cold line and expect good results. I added several inches of insulation when I installed mine but looking back I probably should have scrapped the factory foam and installed the lines several inches apart for an ideal installation. Then you can super insulate each line keeping them isolated from one another. With up to forty feet of lineset out in ambient temps, it can be a source of energy loss in the best of circumstances. Another source of energy loss is having to heat tape the drain lines to keep the condensate from backing up into the unit case. I am always wondering if I should turn my oil boiler (baseboard heat) back on and at what temperatures it becomes more cost effective. I installed KWH meters from china on each unit but the meters like much of chinesium turned out to be disfunctional crap. Nice looking lineset covers that were large enough to separate the lines and hold adequate insulation as well would be a much needed aftermarket offering. Nothing in todays world is even close to that standard.
It would be interesting to see if improving the R values for the insulation would significantly drop the power usage. Looking up charts, it seems like attics/roofs are recommended to have at least R38 up to R60 insulation, R18 seems rather insufficient. Obviously redoing insulation would be a bigger project. Understanding how to determine sources of heat losses would make a good video, perhaps seeing if there is a way to prove significant heat loss via the roof's poor insulation.
You appear to have 2 things going on with your 36kbtu heatpump on your 1000 sq.ft. home -- The first (which you acknowledged in the video) is the poor insulation in your roof. R-18 is mediocre for your area of the country. I suspect it should be more like R-50 for proper insulation. This would definitely retain more heat and work your heaters less. The second is the the COP of your MrCool units. I had trouble coming up with numbers, but it looks like the 36kbtu MrCool units have a COP47 value of 2.8; or rather, for each 1kw you put in, you get 2.8 kw out (@ 47F) -- Naturally, this COP number drops dramatically as outside temps get really low (eg. -5 F). In comparison, modern Fujitsu minisplit heatpumps have a COP47 of 4.0+! As much as I like the idea of DIY heatpump installs (go MrCool!), their lower efficiency numbers compared to their competition make me wonder if it is worthwhile for colder regions of the country. Anyway, thanks for the video. Nice presentation.
Things to consider:
1) 1000 sqft home has a higher surface area per volume than a 3500 sqft home. So it will naturally have a greater heat loss due to the increase surface are per volume.
2) That 1000 sqft home is not very well insulated - at least by newer standard.
In Northern California the new electric rate for 2024 is $0.525/KWh. So that really cold day would have cost $59.85 just to heat the house here, suggesting that heat pumps would be foolish to install in the Sierra Nevada.
Holy lord! That is insane. That rate is about 7X what we are paying in Illinois. Thanks for the feedback 👍
Thank you 🙏 🙏 for showing the graphs and breaking it down by temperatures vs energy used.
Totally makes sense to go ground source heat pump vs air source heat pump in cold climate areas.
Ty
Is it because it is "working harder" or is it because it is running for longer duration over the given day?
I was shocked at how much your baseline power usage is. I only used ~10kwh a day last week (laundry day was 20kwh)
Excellent information on the cold temps when a Heat Pump looses it efficiency and a home should have gas or oil heat source to take over when it is very cold -- (looked to me like the lines on your chart cross at about 20F) where a person would probably want a furnace to take over the heating chores. I have a Carrier furnace that is about 6 years old and i'm contiplating going to a (dual fuel hybrid Heatpump/Furnace combo) unit when I replace the Carrier furnace.
Yeah, depending on your location you need some alternative heat source for the below 20F days where the energy consumption really starts to slip. A dual fuel is an option and I also know Mr Cool has started to do some geothermal but the installation of the closed loop would really drive some labor cost and take it away from a DIY setup.
It would have been nice to have a comparison in this home. Without that, it is hard to undestand if there is a benefit to having a heat pump at a given temperature.
Love the data on the heat pump and how you laid it out vs. temperature though!
Yeah, I wish I could have compared the old system with similar insulation but since this house was recently rehabbed I didn't have baseline data from a gas furnace or oil burner.
I wish we could do an exact apples to apples comparison between your's and mine but there's too many variables. I have a bosch 4 ton, 2500 sq ft house built in 1965, its built very well but still old standards, especially with the insulation, most windows are new but still got 4 to replace, duct work needs redone because its apparently undersized so I'm still supplementing the upstairs with the baseboard heaters that used to be the primary heat, we're in IL as well ontop of a hill with no cover and really strong winds, my unit is a 20.5 seer and 13 hspf vs the mr cool appears to be a 16 seer and 9.5 hspf. My system has had to kick on the aux 10kw resistant heat grid from time to time but for the most part the heat pump has done well to keep the house at or near 70°.
Totally agree , most of the energy you will find out went to a defrost cycle my Mitsubishi duel multi split , ran every 30 mins in -5 f because the buildings cover 3100 ft and date from 1920 listed historical it’s been a nightmare to heat like you were off grid , and had a diesel and log fire , I brought in to the blurb and had nothing but headaches, insulation and air tightness are key now running r40 in the loft, and 8kwh heat recovery exchanger , walks the best we could get in the house was just r18 , after digging out the basement we installed a floating floor and added r25 underneath with a water bond ,this alone did more than the heat pump in -4 and below , helping retain heat whilst keeping air clean, things really went south sadly due to the one man installer dying in an auto accident, but we were 90% set , the second company which not long after completing went bust (I wonder why) screwed its up bug time, we got a max 64f in negative-4f by -10f we just had 50f , the log fire was the only thing keeping us alive, it got so cold one night a window shattered, the irony was the temp fix with twin me3 coated in building wrap, gap tape around the edge to seal, a bit of left over joust berms cut down to frame and bridge gap between two sections r 25 sandwiched in between with additional air gap made it a little bit warmer . Mitsubishi to there credit came out from hq and we’re shocked , they changed the unit since it had been incorrectly connected up by the second installers and somehow damaged all the connector they didn’t even add a bleed point causing the gas to split internally . Hence the -50f, . Winter two before the power cut -9f we were using 74kwh per unit , then we lost power for 10 days , we moved into the annex which is a new build using a pellet burner and boy did we need it , it’s the first time I’ve ever seen ice and frost crystals on the inside door to the main property. It was that cold. The only things that kept us going was the battery backup 40kwh lfp, and a 25kwh array which just produced 2.4kwh on worst day . Now I’ve going to installing propane tank and tankless combi what a difference, up to negative 6f a heat pump will still work but energy early hits 50kwh per unit once it hits -4 I have the heat pump as Supplement only and rely on the tankless for main heat the irony it was cheaper to both run and heat with the propane, less than 700 dollars compared to 1700 on electric what makes it worse is we lost power when we needed heat , the annex use 450 dollars in pellets but since the has gone up 300 dollars
These numbers seem weird cause my 18K unit uses only 1.5Kw and his is double but uses 7K?! Seems high but when I checked the specs at 41A then it would be pulling over 9K.
Here’s something to think about, 114kw hr/day breaks down to 20A load continuous over a 24hr period. Still at least as twice as efficient as resistance electric heat and way cheaper than fuel oil or propane. At that low of an outdoor temp, I would be willing to bet that the unit was only delivering 30k btu or so.
I would be willing to bet if a larger system (the 48k) was chosen, it would be more efficient on the colder days. Given the small enough difference in sizes, I doubt it would be less efficient overall because it’s still variable speed.
I remember years ago when Mr. Cool intalled that heat pump in an older home in an icebox state and crowed about how it kept the house at 70, even when it was -29 out. They later did a follow-up video and proudly showed off the power bill which read at 2200 kw-hrs. 2.2 megawatt hours?!? Maybe electricity is cheaper there but compared to Michigan natural gas prices, my electric bill would be $300 a month. So thank you for lending real world perspective and real numbers behind running a heat pump in the cold. I do plan to replace our aging gas wall furnace in the addition with a cheap mini-split, but that's for supplemental heating and cooling, not our main source. Currently, like it or not, our single stage 92% AFUE natgas furnace works in this old metro Detroit home...
Where I live in North Dakota (same state as that Mr Cool video) our submetered electric heat works out to 5.5 cents per kWh- among the cheapest in the US
3500 kwh wasn’t uncommon for me last winter with electric strip heating. I installed an inverter heat pump this year instead, i’m praying for 2200 kwh this winter.
I live in NYC with average temperatures around 32 degrees and above. If I would use heat pump instead of my gas boiler I would probably pay twice for electricity according his numbers, and I don't even count cost for unit and installation. I will keep my gas boiler.😂
Time to improve your insulation and weather stripping. A 1000 sq ft house heat load at 0 deg F should be about 15,000 BTU. If you had insulated first you could have installed a much smaller unit.
Hmm. I'm inspired to do this on my Mitsubishi multizone split heat pump with two central air handlers.
That's a very good study and I was surprised at the electricity used. Pushing 40 KWh at 30 degrees is a bit high and confirms what I thought about heat pumps. They might be a descent option if the temps don't stay in the 30's for long. Better options would be wood stove, nat gas, propane and geography. My furnace is using about 1.3 KWh/day plus natural gas which was $22 for 1 Dthm of use last month (furnace, stove, water heater). Helps living in NM but does get cold at night. Heater actual runtime up to 2 hours a day. I too lived in IL, time to leave Scott, weather and taxes are killers there.
Yes, I would think that attic insulation as being insufficient at those temperatures. Probably a more comprehensive test would include heat loss on the outside or through the attic.
Wow! I like the graph and table. Good details too. You got to up the R-values on that home!
This little house is tough the R18 roof is actually rigid foam on top of the flat roof decking under a membrane roof. Kind of limited without an attic space.
I live in Manitoba Canada and building code in my area is R30 walls, including basement, and R50 in the ceiling. You're basically heating 2-2.5x the actual square footage. You are mis-representing the efficiency gains by heat pumps... plug these numbers into a heat loss calculator and make another video. Apples to apples not apples to pineapples...
Mr Cool also has a gas furnace, would have been awesome if you had that and compared usage of the heat pump alone vs the gas furnace alone in the same space.
How insulated are these houses, and have you done a blower door test if so what is the air change rate?
I was thinking the same thing. One therm of gas is equivalent to about 30 kwh of electricity. So worst case Mr. cool used the equivalent of about four therms of gas. Need a cost comparison of gas vs. electricity where he is. Where I live that one high day would have cost $40 in electricity but only $10 in gas. However he is talking about trying to go off grid. It would be possible but you would need a couple hundred kwh of battery storage, maybe 30kw of solar and lots of sun on those ice cold frigid winter days.
These systems are great for small square footage area's and more milder winter areas..My minisplit is smaller but combined with a very efficient wood burner, and some diesel heaters for extreme temps and redundancy..My place is only 600 square feet..My garage is 800 square feet, but I heat that with a separate wood burner and propane heater..But my solar handles all of my electricity..
Yeah, that is a much more practical setup and let alternative heat sources handle the heavy lifting. Thanks for the feedback.
Are you able to share what your set temperature was on these coldest days ? Was it set at one temp to maintain all day ? Heat pumps arent as effective at massive set temp changes (ex above 3 degrees), which is why so many recommended leaving them set at one temp and running all day
One thing I love about having an ecobee, is that there is a website called beestat that help you determine at what temp your heat pump pump is unable to keep up with heating your home and the outskde temp. Definitely check that out
The thermostat was set to 71F and held constant. That beestat page looks interesting, thanks for the heads up.