For me I am slightly oversized with a 5 ton air unit because a 4 ton unit is not enough. System ran constantly on a 4 ton and humidity stayed high 60's. With a 5-ton single stage without a variable speed air handler I had some mild short cycling on the cooler summer days it would run 10 minutes or less at a time and then shut off so my HVAC company installed a variable speed air handler and 2 stage 5-Ton heat pump which solved that problem instantly and now my humidity stays between 45-55% im on the deep southern border of Arkansas my home is a 2800sqft Manufactured triple wide it's measurements say I should have a 4 ton hvac unit but with a 4 ton the thing ran constantly unless i set the temp above 80°.
@@SRaveN71 static pressure test we're done and they seem to believe it was within normal range the only thing different was they added another return from the other end of the house. Place is actually big enough that the manufacturer that the triple wide came from when I looked it up on the data sheet each section of the trailers ductwork was designed for up to 72,000 btu's of climate controlled air. There was a whole bunch of baffles that they had to readjust all through the belly duct that they had to go in and adjust to accommodate the higher air flow static pressures are still less than 0.38 at all of the supplies running 100% airflow.
Had the bedroom on the west side was always to hot in the evening, one contract said a new bigger unit, An old friend that I had not seen in years that does HVAC stopped by and said that my unit was the right size it was there was too long of a run using flex duct. ( after his rant about idiots with licences) All he did was put in a run of insulated metal duct which lowered the static pressure Problem solved under 200 dollars vice a quote of 6500 for the new system and ductwork. You talked about this in your video and it was the first time I hear a crayon level explanation of why I needed tp do this. Good job sir.
We had mold in the area right above the cooling coils because the house we bought had an oversized AC unit by at least 2 tons. It didn't run long enough to dry off the coils and because it was oversized, the more powerful fan would blow the water off of the coils onto the box above, causing the mold. So we had mold in our AC system, high humidity and super cold air blasting from our registers. Everything is working great now that we had the whole thing replaced with a properly sized unit.
I had a 3 ton Rheem in a 2.5 ton home, and loved it. Cooled or heated perfectly, but now replacing it and being told I need to use a 2.5 ton so air handler will fit the attic space, so worry the system will run too long. I also took down a huge oak tree that shaded the house, so worry it will prove even more challenging to cool the house. I need to keep shopping to find a 3 ton that will fit the attic space. Super useful info. Thank you for the video!!!
Thank you for this comment. I have a 2 ton. I have never felt it was big enough. Everyone I speak to says what's your house sq ft. I tell them and they say that's it you have the right size. But isn't there more factors than sq ft. We have an apartment in a bi Level that is only half sunk. So 2 Stoves, 2 washers, 2 dryers, 2 dishwashers, 2 microwaves etc. Plus 5 gaming Computers running in the house. The AC seems to run non stop. and fights to meet the set temp. if it runs all night it will get to temp over night but if it goes up a degree during the day it will not come back down till over night again. I am thinking of forcing them to put in a 2.5 ton. What do you think?
I've gone oversize in my last 2 properties. Mainly because the previous systems were undersized. But the systems got were variable speed and multistage compressors. I also had a dehumidifier installed as well.
Interesting. I may be going halt a ton oversized (calculated need 3.5 ton, but unit comes in 3 or 4 ton only). However considered unit is 2-stage, so maybe running in the lower stage most of the time will result in longer running and more de-humidification, even in oversized 4 ton unit?
@ckp2ator389 it's possible. Alot depends on if it monitors humidity and will overcool to maintain humidity. Granted I'm no hvac expert but don't see going a half ton larger for a two stage would be a bad idea.
@@qbanb8582 Thx for your reply. I wasn’t planning on upgrading to a communicating thermostat so probably won’t have humidity monitoring. The contractor also offers a single stage unit that does come in a 3.5 ton so I might consider that instead. Do you know if an oversized unit would be better at pushing cool air to a second floor?
@@ckp2ator389 I dont know. If the second floor was 2 or 3 bedrooms I wouldn't try to cool 2 floors with one unit. But I also live in Florida where its hot most of the year.
@@qbanb8582 You illustrate that where you live does make a big difference. I’m in Michigan where the winters can be brutal so my primary focus is the furnace. We have some weeks of hot temps and humidity but nothing close to your locale. On my complaint about hot upstairs and cooler downstairs, contractor suggested ceiling fans upstairs or zoning system with dampers in the ductwork.
If you were closer to us, you would have absolutely had our business! we have a new inverter HVAC now. we originally had a NO SEER (pre R410) system years ago… you could hang meat in the house! it got sooo cold in the summer but the electric bill was $400-500 month. we went to a 13SEER Amana conventional HVAC and while the electric bill came down, it wasn’t very comfortable. Most recently, we bought a Mitsubishi Inverter HVAC and it ROCKS!!! And out electric bill has plummeted 😊
I have a 3k sqft home with an additional 1.2k sqft of basement conditioned space. We downsize from a 150k btu furnace and 5 ton ac to a 120k btu 2 stage 4 ton 3 zone system. It is insane how much better the new system works. The installer did a manual J calculation and the slightly oversized for 2 zones and then used a 2 stage system. I would say 85% of the time it stays in stage 1 and the remainder is when 2 or 3 zones call. We’ve had 105 degree summer days and been as low as -15 on winter days. The system keeps up and is comfortable. Long story short, insist on them calculating loss and a knowledgeable installer that knows staging and zoning…. It’s worth the extra money!
First off all, I want to state clearly, I am not in the hvac industry, I am an homeowner, only! However, I have been interested in hvac for many, many years & have gathered all the knowledge I can. I believe every hvac contractor should first & foremost establish from their customer how they plan on using their system. What I mean is what set point or design temp are they hoping for. Then is the customer going to use steep set back temps at any time! If they are going to use steep set back temps then the hvac contractor has to size differently, for this! Myself, I believe sizing should be as close to set point temps as possible so system runs most of the time, rather then cycling off & on. This is why an accurate manual “J” is important, with modifications that reflect customers, expectations.
We are in the Sierra Foothills. Hot as Blazes in the summer and DRY. We’re next to a River (Steep Cold River) and our humidity is around 20% drier than a Popcorn F@rt. No humidity issues here.
I absolutely agree with 90% of what you said but there are times where a dehumidifiers are needed where high temperatures (100+) occur then very humid days with moderately high temperatures, the system cannot compensate for these variables. Duct work sizing is often miss sized mostly returns but can be overcome in many cases
I only have humidity problems on Spring and Fall nights when the A/C hardly runs. Outside humidity doesn't matter on hot days, the A/C runs long enough to dry out the air.
Duct work often has a compromised kink point. Common place is return air vent inlet routing to air handler. Seems like all the attention is paid to outlet ducting and vents and inlet return is an afterthought based on remaining space available.
By the numbers my house calls for 3TON but they installed a 3.5 TON because house has plenty of windows. When I replaced the system i went with a 4 TON system because Nevada is mostly hot air, so far my bill has dropped quiet a bit. I suppose switching from 2x 1in 20x20 to a 1x 4in 20x20 helped too
Thanks for the video. What happens usually if you go above 0.5 above the required tonnage? Will your electricity bill increase cause of bigger tonnage or decrease due to faster cooling or stay the same due to size of room? please explain in new video possible. Is it advisable to go above? I am in Texas so its very hot
Hello, I've noticed that the new 410a 3 ton condenser units are shorter than the old r22 3 ton units. Is there a reason they are shorter. Is it the different refrigerant?
Any feedback on figuring out a ducted heat pump size in a new build ICF home. R60 attic insulation. One level, Atlantic Canada, slab on grade, 2250 sq ft. We’ve had contractors suggest anywhere from 1.5 ton to 2 ton. Most online calculators show that as very small for the climate and square footage but not sure how the ICF factors in. Trying to make the most educated decision.
Question : my return air duct is 16”, it should’ve been 18” Can I add a 4” flex duct return to my return air plenum? - I don’t want to have to replace the 16” because it’s costly
I recently moved to Fl. and the ductwork in my house is the square or rec, and several rooms are not receiving good air flow. I was in the hvac business years back and we installed metal size being diminished the farther away from the unit, never had a complaint round air flow helps the room receive good flow.
Round ducts have a static in general. However, there are tons of houses with square duct that’s sized property with no issues. Sounds like your issues are more with sizing and less about static at this point.
An HVAC contractor did a load calculation for my house and determined the cooling need to be 35,674 BTUs. The 2-stage A/C I was considering comes in a 36K (3 ton) and a 48K (4 ton) size. He recommended the 4 ton to be sure there was ample capacity. Do I risk over-sizing my unit (my current unit is 4 ton). Other option is their 1-stage and less expensive A/C does come in a 42K (3.5 ton) size. Would this be the better option?
What are your thoughts on running a manual J heat load clac before installing a HVAC system? Almost every HVAC contractor I got quotes from never ran a manual J and would just look at my house, the old unit, and eye it. With no evaluations of the renovations and changes the house went through over its lifetime, including some duct work changes. Most just wanted to replace with the same tonnage but one tried to upsized my system because he "felt it was needed" but didn't run any calcs, which was madness to me since the house had windows and insulation upgrades over its lifetime. This was for single stage heat pump quotes.
I'm in Maryland in a 2.5 story 1800 sq. ft. drafty stone home built in the 1840's. The primary heat is radiant and I have a 2.5 Ton system that was installed in 1997 that is rusting out. I've had two estimates for a ac and heat pump system in the past two days. One for $8800 for a 2 Ton Carrier system and one for $7500 for a 2.5 Ton Goodman system. The guy that spec'd the 2 ton said that the 2 ton is plenty and I could go to a 1.5. The other guy said he would prefer to put in a larger 3 ton in but because of the limited space he would have to put in a 2.5 ton. Two questions, one are these prices reasonable and two which system sounds more appropriate for my situation. Thanks
Every market is different. So I cannot say whether their prices are good or bad. That said, it sounds like you should have a company do a proper heat load calculation to find out what size system you actually need. Depending on how long you’ve lived there, you will know if the 2.5 ton system was at least big enough to handle your home.
I live in md( silver spring) I also have a smaller house but I'm getting a 3 ton only because that's what's in the house now. My quotes are both 3 ton 2 stage heat pump+air handler. 7k for both lennox and bryant two different contractors.
Having issues with an oversized central AC in Minnesota. System was short cycling on and off every 5 minutes in moderate heat. Replacing the original round Honeywell mercury thermostat with the new Honeywell round non-mercury thermostat helped. We also added a delay on break timer to the condensing unit, and set it for 10 minutes. The temperature needs to be set to 66 degrees to get adequate humidity removal. With the new thermostat and timer, we get about 3 on and off cycles per hour, vs 6 to 7 cycles per hour before the modifications. Sometimes the air handler comes on in 8 minutes, but the condenser is held off for a full 10 minutes. The house is much more comfortable, and we are attempting to save wear and tear on the condensing unit by avoiding excessive on and off cycles. Is this reasonable or would you have done things differently?
It is a 2 story house, 1960's construction with 4" duct work. The upstairs was always hard to cool, so the contractor installed an oversized unit. The thermostat is on the 1st floor, and it cools very fast making the condenser shut off. The 2nd floor gets even less AC now. With the stat set at 66 degrees, I can get the second floor down to 72. The finished basement runs 62 degrees. The constant short cycling was disturbing. The replacement of the stat, and the addition of the 10 minute delay on break timer in the condenser solved that issue to some extent. I don't want to spend more replacing this with a smaller unit. I just want to make it the best it can be.
@@chipmaster56 Sounds like better off with a 2 stage system so it can run at full power to cool off the house at first and then run it half power just to maintain temperature.
I am in Austin, I’m building a 3000sf airtight house with spray foam top to bottom and at least two coats of ecoating on windows. 3 if they face east or west. I am told I need at least 5 ton. I want variable speed but think I risk a lot if I don’t add a whole house dehumidifier no matter what size I get (and feel 5 ton is overkill with the energy efficiency.)
@@jimdavis9581 we actually ended up putting in a mini split into the room that has all the solar equipment. Probably the biggest pole on the energy is the humidifier since we built in winter and built quickly. That will settle down soon, but it’s 106° today and we are comfy!we actually ended up putting in 3 1/2 ton and another mini split also in a bedroom on the west side because it would get a little toasty late in the day. Strikes a perfect balance.
Also, it’s a Daikin fit inverter unit so it’s kind of always running a little bit. But anyone who says you don’t need a dehumidifier in new construction with spray foam doesn’t live in Texas.
Depends on the house. Sizing correctly would be paramount, but installing everything to avoid stale air pockets and proper circulation is a challenge in some homes.
my house has a 3.5 ton heat pump which was builder installed in 2014. Now i need to replace it and one of my HVAC contractors conducted a thorough heat load calculation and told me i need a 3 ton pump instead of 3.5 ton. The area he measured was 1847 sq ft that the pump had to heat and cool. He said he would sell me a 3.5 ton if i wanted it but i dont need one that big. I just want what i need and his calculations were so detailed and we went over it in such detail that i feel i should go with the 3 ton. Looking at a Daiken Fit 17 seer with a 12 year warranty. Does the 3ton pump sound right to you? He also showed me how our builder had screwed up our duct work sizing and will fix that as part of install. Any thoughts on my going with the 3 ton unit? You do great and educational videos.!!!
The confusion lies in multi speed systems. For example 2000 sq feet for heat basic number is 80000 btu of heat based on 40 btu per sq foot. So if it is a 2 stage system i would size the heater at a 80,000/60,000 for an example. The problem is there is nothing comparable on the AC side coming from manufacturers when in comes to high seer multispeed compressors and hvac systems. In western Colorado desert climate witj average temps around 95 snd arid you can oversizeba system and it will run largely at the lower speed most of the time but on those days when it 105 the system can operate at 100 percent, not run all day and it gives more flexibility. So now that i say all of this i am a layman learned hvac in the navy working on aircraft. Have done a number of installs for family and myself and i am wondering if my logic is correct on both heating and air? Seemed to me once i did the cfm calculations for duct sizing and matched the blower speed to the system requirements to the whole house i felt pretty darn confident i had sized the unit correctly and checking my temps and gages on ac obviously to see i was operating correctly.
More than one way to skin a cat but e size the system, then ductwork, and then measure for each room. I feel that’s how most pros do it that I’ve been around.
Yeah the recommendations that I got from 5 out of 6 HVAC contractors in my area when i was looking to upgrade my system where I live it is always best to oversize just a little bit. True most people only need a 4 ton system but sometimes they need the power of a 5-ton system in the summer the solution that was given to me was to install either a two stage or variable speed 5 ton system depending on where a person lives this is a perfect solution. Where I live in deep Southern Arkansas the calculations say I need a 4.2 ton system but since there's no such thing as a 4.2 they automatically downsize to a 4 ton. Which yes true that works perfectly good in the spring and fall when the temperatures are in the mild 70's and 80's but in the middle of summer around June, July, August and maybe some of September when we are getting triple digits or high 90° temps my single stage 4 ton system ran constantly and could barely maintain 78° and would actually climb into the mid 80s in the middle hottest part of the day, which in my opinion a lot of people recommend setting your thermostat at that temperature but yeah nah I'm sorry that is way too warm for my taste to be comfortable so the solution recommended to me was a two-stage 5-ton system or a variable speed 5 ton system with a variable speed blower with a TXV and voila super long run times with 0% humidity removal due to an undersized system solved immediately. It easily gets the temperature down to where it's set quickly and then maintains it with the lower 70% which im told is roughly a 3.5 to 4 ton capacity. Which is sufficient enough 95% out of the year. My electric bills went from close to $800 a month on a 4 ton single stage system to barely $250 with a two-stage 5-ton system because so far this summer it has rarely ran in that second stage resulting in lower energy bills. Most HVAC contractors say "no don't do that it is a bad idea" but people got to remember they've got to make money too so common practice is the undersize you little bit so your system struggles when it's super hot and it breaks down quicker because it constantly runs 24/7 instead of cycling normally.
@@Brad.W Yep. Our 30+ year old 2 ton single stage AC unit was struggling to keep the second floor cool so we recently purchased a 3 ton 2 stage system for both the AC and heater which helped us to get through the triple digit heat wave here in California recently. We have noticed our electric bills for cooling have gone way down. So make sense to replace the aging AC system with a more efficient model. Expensive to get this thing installed but in the long run our lower electric bills will show for it.
Looking for new heaters and new ac for a brick duplex in Phila. One contractor said my ducts would only handle 1 1/2 ton. Another said he would put in a 3 ton upstairs and a 2 ton down stairs….because of the poor insulation and hot sun on the brick. Who am I to believe?
I had to buy a 4 ton system for my upstairs that is 1500 sqft inverter system, due to my cooling demands because my house is in full sun all day, large amount of windows and I have a server rack and electriconics I have. Every hvac guy would only size the system to sqft, and not by device heat wattage either or they wanted to replace with 2.5 ton that was there that wasn't keeping up even in the summer with out the electronics and server rack running.
Sizing should never be base on sq. feet. It should be based on heat load as you indicated. Yes, you need that 4 ton due to the increased cooling demand from those large windows and electronics.
@@NewHVACGuide again Question what happens if my contractor sizes my air conditioner by rule of thumb(sq ft only) instead of doing a proper load calculation?
Lots of things can happen. For starters, systems can be less efficient. Your comfort level is reduced. And you can have issues with humidity in your home.
Hi Josh. For 20 years I had a 15 SEER air conditioner out side, with a 2.5 ton blower in the attic. I could keep the thermostat at 75 and the unit did a great job of getting the humidity out of the house, so it was extremely comfortable. When that unit went bad, the technician replaced the air conditioner with a 17 SEER heat pump and 3.5 ton. I feel like it gets too cold too fast, so it doesn't run long enough and the house feels humid. I tried a few things... I lowered the temperature to around 72, which keeps the house at 70... less humid, but a little on the cold side. Then I tried putting the temperature back up, but closed the dampers a little on the vents in the room with the thermostat. I thought maybe they were blowing on the thermostat, causing it to shut off sooner. I think that helped a little but it was tough getting them just right. Then, just as a test, I taped a sheet of printer paper over the thermostat to see if blocking the air hitting it directly made a difference. I think that worked great. I'm wondering if maybe just putting a thermostat cover over the thermostat would do the trick? Any thoughts?
Probably not. Thermostat needs to be located near the air return away from sources that could interfere. A dehumidifier can help in your situation but RIP your wallet in electrical bills
Air on thermostats... ugh! My A/C cuts on and off too much on hot afternoons, so I checked the thermostat calibration. The temperature of the wall 3" from the thermostat was 76F, exactly as the display showed. The temperature of the thermostat screen itself, 80F!. Stupid LCD screen is producing heat! I experimented with a small fan blowing on the thermostat, and my A/C wouldn't cut on until it got 80F! I guess my thermostat has a 4F compensation for the hot screen. So the fan made things worse.
I installed my own HVAC system this year central air worked great maybe a dumb question but the blower runs harder when the furnace runs than when the ac is on is this due to the ECM motor
@@NewHVACGuide my local gas company moved my gas meter from my basement to the outside they checked for gas leaks and noticed new furnace and central air system he said who installed the system did a nice job I said thank you lol
One thing to consider I've heard concerning ductwork size is concerning air filters. AC techs where I live don't recommend using these "HEPA filters, as it restricts airflow and the blower motor has to work much harder.
I'm trying to figure out what size minisplit system I need. 99% for cooling for 680sqft(living great room/dining room and half of kitchen including range/oven). About a half of the area is 8ft ceilings(kitchen/dining room) and the rest range from 8 -15ft angled ceiling. According to strictly square footage, a 18k BTU system would work. Should I upsize one notch because of the ceiling height and partial kitchen?
Too many variables to answer this question pal. A unit can cause issues if it is oversized. Have your contractor do a Hilo calculation before purchasing the unit
I moved into a brand new house six years ago. The people that remolded house but in a furnace that is to big so it shuts off when duct gets to hot. Can I cut into duct to let heat out? Thanks
What have you seen with the reliability of an inverter heat pump vs just a two stage? The first seems to have higher efficiency, but is there an increased rate of failure? The higher cost doesn't bother me so much as the potentially higher repair costs down the line. If that is covered in your guide, I don't have a problem getting it now. I'm not in the market, but my units are old, so I could be, unexpectedly.
I don’t think they have a higher rate of failure. Since they are inverter systems, they work less hard at times. The only thing we have seen in across-the-board with all systems including inverter, multi stage, and single stage is the cost of variable speed blower motors has increased way more than what PSC motors used to be.
They certainly have more bells and whistles. Air quotes “ more things that can go wrong“ But pretty soon I think they will be all you can buy anyway. So folks need to get with the program LOL
@@TheEngineerd Inverter systems are more intricate with a higher level of control, however due to this higher level control the complexity of the electrical components within the unit equate to more expensive repair costs because unlike a regular air conditioner that has a very basic and simple set of components that operate the unit, the inverter systems typically take longer to diagnose properly, which can start to add up on a bill real fast and when the unit is diagnosed to have a faulty control board, or some other part that is specific to that unit, it can cost a lot more for the parts due to the fact that you must install the OEM part from the manufacturer otherwise the unit will not work. And most of the time when units have brand specific controls that are only used on that one piece of equipment, the price for these parts is unreasonably expensive. A traditional AC unit contains parts that every single tech has on their van that are much less expensive and are easily obtained at any supply house. With higher levels of control come higher cost for repair, labor,and longer downtime due to the fact that a lot times these OEM parts need to be ordered and shipped instead of being available at all supply houses. I think it's wonderful that these systems exist and they have their benefits per application but I value reliability, consistency, and simplicity over a small increase in energy efficiency. This does not mean that I dislike inverter systems it just means I do not prefer them. That is my genuine, honest, and sincere opinion.
Night tone - all good points-I’ve had all three in various houses- that old single stage unit juts chugged along for 22 years, gradually grinding itself to death . Noisy, inefficient, but it was sized ok and didn’t cycle that much, but it was noisy !. Parts were cheap always available etc. then moved to two stage unit-more comfortable in one house, but because it was more efficient higher seer and we mindlessly just used same tonnage, a lot of cycling- why? Lowest it could ramp down was 40%…..more repairs. More recently we Et with full inverter and variable speed ecm fan-expensive but way way way more comfortable - not even close, and critical in humid tepid days in fall and spring. As Ana side I’ve had trane, carrier /Bryant and Lennox, American standard, all are good, -look for the form and look for the actual ethos who do install/repairs, not the owner .you don’t want too big a form-they have huge staffing issues these days-i prefer smaller firms who can retain and train staff. You do run risk they may run into problems if owner retries, does, one staff guy retires, moves etc, but as long as you have a brand that has good distributor in your area, parts available, and many dealers to choose from. You arce good. Equipment wise, I think Lennox gets top billing- very sophisticated and well built and thier communicating thermostats the easier to pe rate and very stable. bUT Lennox insist you only move their products and in most fewer dealers. Carrier overcharges, but in almost any jurisdiction parts are widely available, many forms service so u can lick or chose if one firm lets you down. I just hear more complaints about parts and issues with the than the others and it’s pricing it’s certainly no better. Lennox had some big manufacturing issues about a decade ago but addressed quickly and things seem smooth right now. NB if going with top of the line heat pumps, only carrier/Bryant have heated dehumidification, very valuable if you have long trunk seasons , ie lots humidity, temps I. The 70’s. NB hvac these days is very complicated, most techs are in over the heads, the young ones due to experience, the older because they haven’t kept pace with technology.
just had a thought on what you said, if you have a AC unit that's over kill but have a over kill dehumidifier, would you or would you not use less electricity of course being properly insulated.
I think it depends on the situation. I was just saying generally that a dehumidifier cannot be oversized because it will just reach the humidity if oversized and then turn it off
Well good stuff but sometimes the el cheep o is all some can afford and at the price I have in my inverter splits , I can throw away one a year for the first 4 years and still come in at a better deal, but now if the some of those top tier mini splits would come down some in cost it would be something
So how do you combat those super hot days that happen 10-14 days a year ? A “properly” sized unit will leave you hot on those days. We like to keep our house at 68 during the day and 64 at night.
Add a small mini split unit to you main living area and set in one or two degrees higher than your normal setpoint. It will add capacity when needed and be a backup If your large unit fails. You can get one under a grand.
Lots of words but no information. It's obvious, too large is bad, too small is bad. What is the proper size of a/c based on? What is the proper size of duct based on? Velocity mins/maxs? Air changes? Delta T?
Very informative video. Lots of quality information communicated in an easy to understand manner. I am renovating the second floor of my cape cod style home. Currently steam radiator for heat with window air conditioner units for cooling. Mold has been an issue due to lack of ventilation & increase indoor humidity due to steam heat. Located in NJ so humility in the summer months can also be high. Looking to modernize our HVAC system during this renovation. Ductless system seem like a great technology innovation but concerned about the aesthetic appearance. Any recommendations for most visually appealing ductless systems?
Hi Joshua! Great video, very helpful - like all of your others. I have a ductwork sizing question. I got a couple heat load calculations done for my 2nd floor area as I shop for a new heat pump, and I've gotten estimates of 4+ tons needed. I've used 3 tons since I bought the home years ago, and am replacing the second floor heat pump. I would like to go to 4 tons because I've always felt 3 tons was at least slightly insufficient on the hottest and coldest days here in Portland, Oregon. Two bidders flat out said my ductwork supply lines were too undersized for 4 tons. I have 12 supply registers (6 inch pipes to each), and one rule of thumb quoted to me was approx. 100 CFM per register, and each ton needing approx. 400 cfm, leaving me 400 cfm short for 4 tons - way too short they said. I was going to go with a communicating variable speed heat pump and air handler (either Trane or Goodman), so felt like I did have some "cushion" against constant strain on the system. Your thoughts on this? Do you agree with the rules of thumb cited to me?
Variable speed systems do not remedy a duct sizing issue. Although forgiving, the systems will never operate efficiently if the ductwork is undersized.
Need advice, I have a common 3 Ton split system gas furnace. My compressor failed after 15 years of service. I recently purchased a new 3.5 Ton heat pump condenser as a replacement. I would like to take advantage of the heat pump technology and use the gas furnace as backup heat. My question revolves around the specifications of the new replacement evaporator coil. I noticed that most heat pump condenser units are married to an air handler with electric backup heat, instead of an evaporator coil box on a gas furnace. I understand that gas heat is possible as backup with a heat pump, but I'm confused about what modifications need to be made to the evaporator coil TXV. Please advise if there are special TXV for heat pump evaporator coil configuration and if there is something that is needs to be done to the furnace. Thanks Kevin
I'm having to add cooling into my 4yr old home because when built (not by me, model home) they way undersized the cooling. 3.5 ton 1st floor and a 1.5 ton 2nd floor units on a 2600 sq ft 2 story, with no trees. Oh yeah, in Houston lol. It seems that the AC industry in general always wants to use base load calculations and call it a day, at least around here thats what they do in residential and commercial.
Good video, I have a question. I have I have a metal garage 20'X12' 240 SF. It's all insulated with 1" foam except the garage roll up door. I want to install a mini split 9,000 BTU or 12,000 BTU?
Not an HVAC tech but personally, I'd go with 9K BTU. I'd also look into ways to insulate the roll-up door to avoid condensation. I'd try something like reflective bubble insulation. If this were a garage I only wanted conditioned occasionally, I'd go with 12K BTU to get it to temp quicker.
Deffinatly go w 12000 and in that situation 12k may actually not be enough depending on your location. Always do a load calc. Insulate the garage door aswell like Dan suggested
Does anyone know what size rectangular ducts are needed for a 420 square foot 3 room addition? It has a separate furnace, 24 foot straight run and six 6" side vents. I got 8" x 16" supply rectangular ducts but haven't installed them yet as I'm not sure if they aren't too big for heating.
I am trying to replace my hvac system. Heat pump. Old system is 2.5 tons but l want to upgrade to 3 tons. I am in Georgia. I want to know if it will be ok. I get 17 sq ft
Going bigger is not an upgrade. An upgrade is getting a better technology in the unit. Going bigger if it is not adequate the application will be a DOWNGRADE in efficiency, comfort, humidity control, longevity Most systems are oversized and most contractors will oversized you
I have about 1100 sq ft townhome on a lake with a direct west view in south Florida. We have lots of humidity here. Prior we had a 2.0 but I felt it wasn’t blowing enough or cooling the house down as good as it should. I talked with the HVAC person and he said 2.0 or 2.5 would be okay. The first day it took a while to bring down the humidity. Overnight it brought the humidity down from 65% to 53%. Thankfully. Phew. I thought we were screwed. We got a Bryant.
Awesome video! Quick question I live in Canada on the West Coast. My house is built in late 80s 2 storey home, We are looking to add Central AC to the main floor 1450 sqft (3 beds, kitchen, living, dining, hallway) one contractor said I would require a 2.5 ton one said 3 ton is it safe to go for 3 ton if I choose a dual-stage system to prevent cycling?
Please help !!! New 5200 sq ft first floor with a 500 sq ft bonus room above.Foam in attic and rockwool insulation in exterior walls. 2 Units 4 ton each for a total of 8 tons. living room 14 foot ceiling and all other rooms 12 foot. Does this size make sense? I would really appreciate any help on the question above....
I had the 25 year old unit in my parents home replace 7 years ago. The old 3 ton Lennox was a good workhorse but on normal 90-93 degree summer days it would run all day to maintain 75. On 95+ days or when the stove and oven are used a lot it would lose ground. Their HVAC guy (same one who put in the old one) replaced it with a 3.5 ton Trane (still single stage)and what a difference. With the variable speed blower it dehumidifies better than the old one and they were able to raise the set temp to 77 because 75 felt colder than the old unit. On normal days it runs 15-20 minutes to maintain 77. Even at 75 it’s run time is 30-40 minutes on normal days. On the occasional 100+ days it runs for hours but has no problem maintaining 75; at a 77 set temp it would still cycle. Big drop in their utility bill as a result. The contractor gave most of the credit to the variable speed blower’s ability to dehumidify by running a low speeds at startup and slowly ramping up, not the extra 1/2 ton. He said it’s not that much of a size difference and the the 3 ton running all day to maintain 75 is considered optimal performance. But the variable speed blower of the Trane makes it feel cooler. Also, he says Trane and some others are making larger condensers compared to older units with the same tonnage. Combined with the swept wing fan blades the Trane is able to dissipate heat better than the old Lennox and use less energy at the same time. Compared to their old Lennox the Trane is huge but ironically it’s refrigerant capacity is less than the old 3 ton.
My house is 1100 sq ft with 7.5' ceilings and 111 years old. I live in SW Missouri with high heat and humidity. I am getting a heat pump split system Trane xr15 2.5 ton with an S9X1 furnace. Would a 2 ton system be better?
@@NewHVACGuide Thanks for responding. I used another calculator and entered my SW Missouri climate as "like Houston" and got 2.5 ton. The contractor was born and raised in my town, so I will trust him.
I live in Kansas. Getting ready to have hvac system replaced. Little over 1800 sq ft home with partially finished basement and 10-11ft vaulted ceilings on main level. Currently have a 3 ton system that is original to the home when built in 2003. Should I go with a 3.5 ton or stick with a 3 ton system? Our current ac has never worked great since we moved in 2016, but that could have been because it wasn't working properly, not necessarily because it's undersized. Thanks
You should have a ceiling fan in a house with high ceilings. This will help your comfort level. Make sure your house is insulated very well. 3 ton should be good. Oversized unit will waste money. Oversized units will cool the house quicker but will not dehumidify the air as much which is another thing you should want to do.
I live in a 3600 sq. ft. home in Arizona so it is hot. I have a 2 ton unit which covers my master bedroom, closet and bath and my 4 year old Lennox unit does not adequately cool. There are 2 vents (10 in vents) in master and it cools fine but the bathroom has a little 6 in vent and so does the closet and closet blows barely anything so it is stifling in there; and the bath is the same; just blows slightly more air. We had Lennox rep who installed system and they said it is working properly but it is miserable especially in summer. We have solar panels on our home and our bills are still over $200 a month and that is keeping our units at 78 during the day; even if you turn it down in the afternoon the thermostats will not reach 75 or 76. I am miserable. Our old trane units in a much larger home cooled within minutes? What to do? I am aware the builder uses units and not square footage and the air flow is not cool. It is a long summer here. Some neighbors have had to reduct ($2000) and had to order new larger units.
Wow. What a pickle. I recommend finding a good contractor local to you and going with what they recommend. Every market is different. So find someone awesome and go from there.
Thanks for sharing this, I live in East coast I have two storey house 2100 sq, I hired a contractor to install HVAC and recommend me putting 5 tone AC, I'm concerning if is to big for the size of house?
Trying to get a new gas high efficiency furnace here in Massachusetts. My old one is a 96000 btu furnace with pvc flue. 2500 sq ft house , built in 1995. Why am I getting some companies say I need 80,000 BYU’s and some say 100,000.? Old one seems ok.
2500 sq ft house built in 95 could very well only need a 60k, please have a manual j load calculation done. if 60k is a little small, look into lennox and rheem which offer furnaces in between 60 and 80. I'm in southern ontario canada, same kind of northeast winter climate and 80k condensing furnaces go into 3000-3500+ sq ft homes. It takes either a huge or very poorly insulated home to need 100k in northeast.
I live in bakersfield got a new house 1882sq ft and has 9'ceilings and has 11 windows plus sliding door and they installed a 2ton 24000 btu and we cant cool house down the coolest it has been is 78° in the morning but 86 around noon who will be responsible builder? inspector that passed it? hvac company? or am i going to have to eat it just not fair its a new house and is under warranty
I recommend finding a good contractor local to you and going with what they recommend. Every market is different. So find someone awesome and go from there. Then have a proper heat load calculation done even if you have to pay for it.
Im in Hampton Roads, VA. My place has a old 2.0 ton unit (from 2001) but it struggles (1800 sqft) on hot days it does hit thermostat temp. I had a quote from HVAC company to a 2.5 ton system and 2.5 vap coil. Should a 3.0 ton be used instead?
Thanks josh for cool vid. Im a new homeowner and put in a new system end of last summer. I have one zone duct. Gas Furnace and ac coil on too, in basement. Condenser is 5 ton, 16 sheer. 2k sq foot. Hard Ducts goes from basement to attic and branches out throughout the house. Problem im having now is in winter. Too hot upstairs & too cold down stairs. I tried resolving it with nest sensors. But downstairs is just weak. I even tried adjusting ceiling diffusers, still hot upstairs. Upstairs is all flex ducts from attic to second floor. Flex ducts looks quite big. Should i reduce the size of it? I havent experience the summer yet with this system. I am assuming it will be hot upstairs and cooler downstairs?
We just ordered 2 Amana 311 seer 16 air conditioners for our 2 story high ceiling 2900 sq ft house. They arrived today and they are huge compared to our old air conditioners. Are you familiar with the model we got and do you think it’s too much?? I live in California btw
All systems today are like that, I had mine replaced about 7 months ago. I have a 5 Ton 19 seer Daikin Heat pump and it is much much bigger than my old 1994 5 ton York. They have to be large to meet efficiency standards and I dont know how old your last system was but if it was a R22 which is more efficient than R410 what is used today but R22 was bad for the Ozone.They need larger coils to remove the heat with R410 than they did with R22.
@@wes2460 Thank you for sharing. The old units were installed when the house was first built in 2005. But one of the units was making a thud sound when it turns on so now we are seeking to get a replacement. But nextgen is giving us a hard time
Good info, although a lot of these issues aren't really done by the contractor. Most of this would be taken care of by an HVAC designer/engineer not necessarily a technician or contractor unless they are partnered with one or are a full design build company. A lot of the time when I've had to redesign a home the issue is because the design was not followed by the original builder and residential codes are way more lax than commercial codes especially when it comes to duct work. Most duct work in residential is lower quality soft duct which usually a wire spiral frame with insulation and a cloth and plastic membrane vs spiral hard metal or square metal duct work wrapped insulation. Unit selection in high humidity usually has a hot gas reheat coil which warms cooled air back up strictly for humidity control or has a humidistat and variable refrigerant control to ramp down for steady air volume. These are required in commercial applications and not so much in residential. Over sizing tends to occur when installers dont follow schematic design or install things designers hate like 3 way duct splits which I personally despise as a designer. Another issue is duct runs over 100' due to static pressure loss. The fans in residential units just dont got the static and volume for that length. This could be due to roofers boxing out the wrong spot though and not the installers. All in all get youraelf a contractor who partners with an engineeer or a design build.company if you have major issues
@@NewHVACGuide One was recommended by father in law and the other by my friend lol. Don't really know either one. The friend of the father in law is 100 bucks cheaper. So he would install the lennox. Which brand has cheaper parts?
Honestly, if I were talking to my own family, I would probably tell you to go with the Bryant. But that’s just because I’ve had a few bad experiences with Lennox. However, I have friends that will only install Lennox and love them
I used the coolcalc website to do a manual j calculation; Using my address in San Antonio, TX, the "outside design conditions" temp range by default is between 31 and 96f. This results in a load calculation of about 36k btu for cooling. But, we regularly hit 100+ in the summer, sometimes reaching up to 110. If I put 110 as the high for the temp range it calculates around 47k for cooling. Would we be better off getting a 4-ton unit to handle those hotter days or could it be too much for most of the time when it is below 100 and cause those humidity issues?
You can only size it as large as the existing duct work allows. A general rule of thumb is 400cfm per ton. That is a VERY general rule of thumb. Size it properly with static pressures and either build new duct work or go with what the duct work will allow.
Thanks Josh. I'm in northern Virgina and am replacing my existing HVAC; 35 yr old single family home, around 1800 sf, new windows & siding. My current maintenance company proposed to replace my old 3-ton AC / 100-BTU (2 stage) furnace with the same sized equipment (AFUE is 80). For the second proposal, the contractor came to the house and said the current furnace was larger than I needed, and proposes to install a 3-ton AC / 80-BTU (2 stage) furnace (AFUE=80). The second guy was correct when he guessed that my current system probably didn't kick into stage 2 hardly at all in a normal winter. Any thoughts to share? Why should I go with the 100-BTU furnace if the second stage is rarely used?
We typically match a 3 ton system with an 80k btu furnace and have never had an issue. Did you ask the first company why they want to stay with the original size?
Never automatically assume you can replace like for like. The equipment you have now could be undersized, correct or oversized. When replacing, always do your own calculations for what size equipment to install, so you don't possibly repeat another's mistake.
Are very interesting I've been offered an air source heat pump , it came out of a friend's restaurant, it's an 8kw unit AOYG24LFCC, quite big as was thinking 3.5kw would be ok for my small house. Can this large unit run at the lower power? This machine was built in 2013
@@NewHVACGuide sorry should have said it was fujitsu heat pump. If I fit a large one will it run at a lower current , I see it's max is 16a , where I think 3kw was about half that. What steps do these run at?
That would be big in our area. Maybe there is some thing more to the story like our ceilings for insulation issues. Have a proper Heat load calculation done and you will be good to go
Depends on when the home was built, how well is it sealed, are windows only single? If you have an old crappy house and from 70s, yeah 3ton is pretty common in south texas. But if you have a newer home, say from 2015 or so. a 1.5 what you would likely need.
I just know my furnace is oversized for this house. It's 1321 sq ft, and the furnace is 80k btu. I set the fan speed to low, because the house can heat up so quickly at the fastest speed.
Just changed my ac unit I had a 4 ton and it was struggling and my thought was bigger size and I got a 5 ton Goodman but now I’m realizing I made a huge mistake reading on it and kinda bummed 2000sq ft 2 story I’m in Houston it gets hot my 4 ton was old and it was on all day and night so my thought was in need a bigger unit the guy said okay what ever you want and now I’m stuck between what can I do? Add a dehumidifier but I did for the reason that my light bill was $500 I was like I need it replaced it ASAP then I did it the house is cold but now I’m thinking of solutions.. any thoughts? Just dehumidifier I read that I can add a duct to the garage to get rid of some and add a dehumidifier?
@@NewHVACGuide best option would be to buy it again at 4 tons right? Man first home and I wanted to do something good but turns out it’s worst can I change just the outside unit add a uv light and dehumidifier? Or change both? He said the inside unit has low speed would that work?
@@eduardomedina4328 just make sure it’s an AHRI match but yes. Sometimes condensers are matched with larger indoor units for higher SEER ratings. And that would lower your capacity.
I live in a 1,049 sq ft condo in Georgia that previously had a 2 ton regular A/C condenser and air handler/coil. Just had a company quote me a 1.5 ton Daikin DZ14SA0181 Heat Pump condenser with a 2 ton Goodman AWUF250816 air handler/coil. Does matching a 1.5 ton condenser with a 2 ton coil seem right? I was also originally interested in the Daikin Fit but they said it wouldn't work in my condo because the air handler I would need would be too big to fit in the utility closet. I was surprised they didn't make a wall hung air handler yet for the Fit. Also, thanks for all the videos you put out. I'm really learning a lot about HVAC and find it fascinating...
Hello! They do not make a closet air handler for the Fit unfortunately. It’s not uncommon for the indoor unit to be a little bigger than the outdoor unit. It just can’t be the other way around.
@@NewHVACGuide thanks so much for the info. Doing something like that won't void the Daikin warranty or anything? I just thought it was a little strange because out 6 different quotes I received they were the only ones who quoted a system that wasn't sized the same. Too bad they don't make a Fit closet unit, I would think that could be a huge market for them.
Nice informative video. Have a question, I live in the Midwest and could get really hot and humid in the summer. My house in the main floor is around 2000 sq ft. My unit is a 3 ton ac/furnace 2 stage. It working good except for one room that has a cathedral ceiling, I am guessing 15 ft high. Only one register but no return. It gets really hot in the summer. I cut off the bottom of the door but still really hot in the afternoon. My question is do I need a return vent or supply vent, or both? The room is comfortable in the winter. Thank you.
Goodman is the cheapest you can get along with a couple others. Nothing cheapest in anything is good and worth having Reasons to buy it: Selling home Rental property that will be sold in less than 10 years Flipping home Can’t afford anything else
Sizing isn't my concern. What I find is this Carrier unit. It's small. 9,000 BTU. But they call it 42 SEER... I don't believe it. Are they just making up numbers? For my application, I need all the efficiency I can get. It's not a matter of cost. It's a matter of being utterly impossible if it uses too many watts. It's not a matter of "being worth it." It's a matter of "it can't be done unless it's silly-levels of efficiency." Which makes me a perfect target for made-up numbers...
The number one thought for me, you don't make cold, you remove heat. Keep coils, FILTERS and duct work clean. It won't matter what you have if it is clogged.
I have to disagree with oversizing heating equipment. For one, if you heat a spade too quickly it’s super uncomfortable. Also, depending on how oversized the equipment is, a gas furnace for example, it could cause premature failure of the heat exchanger and premature failure of the blower motor as well as inducer motor. Not to mention persistent tripping of safety limits.
I think in most cases those issues would only happen if the system is oversized and the ductwork is not. But if everything is sized correctly as far as the ductwork goes, you would just have a system that short cycles a lot
@@NewHVACGuide 9/10 if system is oversized then ductwork would be undersized. I’m not talking about a 60kBTU furnace where there should be a 40… but definitely a 80 where there should be 40 or 100 where there should be 40. Also with it heating the space quickly like that it will be very uncomfortable and a lot of hot and cold spots/areas throughout home
By the way, it takes 144 BTUs to melt one pound of ice in one day (24 hours). If you have 2000 pounds of ice (a ton) it is 288,000 BTUs absorbed to melt that ton in one day. If you divide that by 24 hours, 288,000 BUTs per day/24 = 12,000 BTUs per hours per ton. So a ton of cooling is 12,000 BTUs over an hour. PSA announcement. lol!
Hoping to pick your brain. I have a 100,000 (input) btu 80% Gas furnace in my 2 story home that is 2500 sq. ft. but there’s a 3 ton AC unit here as well but both units do great heating and cooling all season(s). Since this furnace specs are 5ton, 2000 cfm ECM motor, should my fan be set at 1200 cfm for the cooling speed? I realize the AC is undersized for whatever reason but it works great. Anything here that you would see as being an issue? Thank you for your time.
My electricity bills more than doubled during summer the inside temperatures in the 80s despite AC being on 72 no one can find anything wrong. The third AC guy thinks it might be undersized. However I'm getting tired of hearing the word I think when I had the AC installed 8 years ago the guy wasn't sure if I needed a 2-ton or a 2.5. so the phrase "I think 'is costing me money. I'm uncertain how accurate a BTU calculator is. I've used two different ones suggest my house should be a 3.3 ton with 9 ft ceilings ,however my living room goes up to 14 ft and I'm not sure how to add in .. If that living room ceiling would put me closer to a three and a half or not. 1232sq ,heat zone 1 , zero shade, the living room and kitchen ceiling goes up to 14 ft So I'm not sure what to go with at this point the other guy informed he thinks I need a 3 ton. However with every calculator showing 3.3 not calculating the higher ceiling I'm not sure which AC guy to go with at this point one says I need a three another says a three and a half
I'm meeting with a sales rep for our local HVAC provider. Mon Jan 29th. They will be providing me with an estimate. If I purchase the $ 300.00 service provided by your website/service will you or one of your colleagues. be able to review the estimate and offer me guidance. I am completely in the dark here. We are replacing a heat pump with a 2-stage capacity. I'm located in NC. I also intend to go through your site to arrange financing. We are receiving some money from our Homeshield warranty.
For me I am slightly oversized with a 5 ton air unit because a 4 ton unit is not enough. System ran constantly on a 4 ton and humidity stayed high 60's. With a 5-ton single stage without a variable speed air handler I had some mild short cycling on the cooler summer days it would run 10 minutes or less at a time and then shut off so my HVAC company installed a variable speed air handler and 2 stage 5-Ton heat pump which solved that problem instantly and now my humidity stays between 45-55% im on the deep southern border of Arkansas my home is a 2800sqft Manufactured triple wide it's measurements say I should have a 4 ton hvac unit but with a 4 ton the thing ran constantly unless i set the temp above 80°.
I need a 3 ton unit here, and I think 3.5 is enough here.
But did you upsize your ductwork to support the extra 400 cfm on the return and supply?
@@SRaveN71 static pressure test we're done and they seem to believe it was within normal range the only thing different was they added another return from the other end of the house. Place is actually big enough that the manufacturer that the triple wide came from when I looked it up on the data sheet each section of the trailers ductwork was designed for up to 72,000 btu's of climate controlled air. There was a whole bunch of baffles that they had to readjust all through the belly duct that they had to go in and adjust to accommodate the higher air flow static pressures are still less than 0.38 at all of the supplies running 100% airflow.
Had the bedroom on the west side was always to hot in the evening, one contract said a new bigger unit, An old friend that I had not seen in years that does HVAC stopped by and said that my unit was the right size it was there was too long of a run using flex duct. ( after his rant about idiots with licences) All he did was put in a run of insulated metal duct which lowered the static pressure Problem solved under 200 dollars vice a quote of 6500 for the new system and ductwork. You talked about this in your video and it was the first time I hear a crayon level explanation of why I needed tp do this. Good job sir.
We had mold in the area right above the cooling coils because the house we bought had an oversized AC unit by at least 2 tons. It didn't run long enough to dry off the coils and because it was oversized, the more powerful fan would blow the water off of the coils onto the box above, causing the mold. So we had mold in our AC system, high humidity and super cold air blasting from our registers. Everything is working great now that we had the whole thing replaced with a properly sized unit.
mold 😲 Ohnoes! Vacate the Earth it's attacking you 😂😋🤭
I had a 3 ton Rheem in a 2.5 ton home, and loved it. Cooled or heated perfectly, but now replacing it and being told I need to use a 2.5 ton so air handler will fit the attic space, so worry the system will run too long. I also took down a huge oak tree that shaded the house, so worry it will prove even more challenging to cool the house. I need to keep shopping to find a 3 ton that will fit the attic space.
Super useful info. Thank you for the video!!!
Thank you for this comment. I have a 2 ton. I have never felt it was big enough. Everyone I speak to says what's your house sq ft. I tell them and they say that's it you have the right size. But isn't there more factors than sq ft. We have an apartment in a bi Level that is only half sunk. So 2 Stoves, 2 washers, 2 dryers, 2 dishwashers, 2 microwaves etc. Plus 5 gaming Computers running in the house. The AC seems to run non stop. and fights to meet the set temp. if it runs all night it will get to temp over night but if it goes up a degree during the day it will not come back down till over night again. I am thinking of forcing them to put in a 2.5 ton. What do you think?
crappy insulation and lots of large windows as well.
I've gone oversize in my last 2 properties. Mainly because the previous systems were undersized. But the systems got were variable speed and multistage compressors. I also had a dehumidifier installed as well.
Interesting. I may be going halt a ton oversized (calculated need 3.5 ton, but unit comes in 3 or 4 ton only). However considered unit is 2-stage, so maybe running in the lower stage most of the time will result in longer running and more de-humidification, even in oversized 4 ton unit?
@ckp2ator389 it's possible. Alot depends on if it monitors humidity and will overcool to maintain humidity. Granted I'm no hvac expert but don't see going a half ton larger for a two stage would be a bad idea.
@@qbanb8582 Thx for your reply. I wasn’t planning on upgrading to a communicating thermostat so probably won’t have humidity monitoring. The contractor also offers a single stage unit that does come in a 3.5 ton so I might consider that instead. Do you know if an oversized unit would be better at pushing cool air to a second floor?
@@ckp2ator389 I dont know. If the second floor was 2 or 3 bedrooms I wouldn't try to cool 2 floors with one unit. But I also live in Florida where its hot most of the year.
@@qbanb8582 You illustrate that where you live does make a big difference. I’m in Michigan where the winters can be brutal so my primary focus is the furnace. We have some weeks of hot temps and humidity but nothing close to your locale. On my complaint about hot upstairs and cooler downstairs, contractor suggested ceiling fans upstairs or zoning system with dampers in the ductwork.
If you were closer to us, you would have absolutely had our business! we have a new inverter HVAC now. we originally had a NO SEER (pre R410) system years ago… you could hang meat in the house! it got sooo cold in the summer but the electric bill was $400-500 month. we went to a 13SEER Amana conventional HVAC and while the electric bill came down, it wasn’t very comfortable. Most recently, we bought a Mitsubishi Inverter HVAC and it ROCKS!!! And out electric bill has plummeted 😊
Wow! Great to hear!
most oversize conditions can be resolved or significantly improved by slowing the evap fan.
I have a 3k sqft home with an additional 1.2k sqft of basement conditioned space. We downsize from a 150k btu furnace and 5 ton ac to a 120k btu 2 stage 4 ton 3 zone system. It is insane how much better the new system works. The installer did a manual J calculation and the slightly oversized for 2 zones and then used a 2 stage system. I would say 85% of the time it stays in stage 1 and the remainder is when 2 or 3 zones call. We’ve had 105 degree summer days and been as low as -15 on winter days. The system keeps up and is comfortable. Long story short, insist on them calculating loss and a knowledgeable installer that knows staging and zoning…. It’s worth the extra money!
First off all, I want to state clearly, I am not in the hvac industry, I am an homeowner, only! However, I have been interested in hvac for many, many years & have gathered all the knowledge I can.
I believe every hvac contractor should first & foremost establish from their customer how they plan on using their system. What I mean is what set point or design temp are they hoping for. Then is the customer going to use steep set back temps at any time! If they are going to use steep set back temps then the hvac contractor has to size differently, for this! Myself, I believe sizing should be as close to set point temps as possible so system runs most of the time, rather then cycling off & on. This is why an accurate manual “J” is important, with modifications that reflect customers, expectations.
We are in the Sierra Foothills. Hot as Blazes in the summer and DRY. We’re next to a River (Steep Cold River) and our humidity is around 20% drier than a Popcorn F@rt. No humidity issues here.
Can you have a bigger Evap coil and smaller condenser. I have a brand new 4 ton Evap coil in my garage and 3.5 condenser.. can I install this together
So my condo, is 1045sq ft, should I get a 2.5 ton or 3.5 ton for all electric heating?
2.5 should be enough.
I absolutely agree with 90% of what you said but there are times where a dehumidifiers are needed where high temperatures (100+) occur then very humid days with moderately high temperatures, the system cannot compensate for these variables.
Duct work sizing is often miss sized mostly returns but can be overcome in many cases
I only have humidity problems on Spring and Fall nights when the A/C hardly runs. Outside humidity doesn't matter on hot days, the A/C runs long enough to dry out the air.
Duct work often has a compromised kink point. Common place is return air vent inlet routing to air handler. Seems like all the attention is paid to outlet ducting and vents and inlet return is an afterthought based on remaining space available.
By the numbers my house calls for 3TON but they installed a 3.5 TON because house has plenty of windows. When I replaced the system i went with a 4 TON system because Nevada is mostly hot air, so far my bill has dropped quiet a bit. I suppose switching from 2x 1in 20x20 to a 1x 4in 20x20 helped too
Awesome!
Thanks for the video. What happens usually if you go above 0.5 above the required tonnage? Will your electricity bill increase cause of bigger tonnage or decrease due to faster cooling or stay the same due to size of room? please explain in new video possible. Is it advisable to go above? I am in Texas so its very hot
It's advisable to get a manual J load calc do know exactly what your ductwork is designed to handle.
Hello, I've noticed that the new 410a 3 ton condenser units are shorter than the old r22 3 ton units. Is there a reason they are shorter. Is it the different refrigerant?
Any feedback on figuring out a ducted heat pump size in a new build ICF home. R60 attic insulation. One level, Atlantic Canada, slab on grade, 2250 sq ft. We’ve had contractors suggest anywhere from 1.5 ton to 2 ton. Most online calculators show that as very small for the climate and square footage but not sure how the ICF factors in. Trying to make the most educated decision.
I recommend getting a proper heat load calculation done by a pro even if you have to pay for it!
Question : my return air duct is 16”, it should’ve been 18”
Can I add a 4” flex duct return to my return air plenum?
- I don’t want to have to replace the 16” because it’s costly
my house has under slab ducts and sloped ceiling no attic spaces more cold in the winter OK for the summer i live in the southwest Okla.
Awesome!
I recently moved to Fl. and the ductwork in my house is the square or rec, and several rooms are not receiving good air flow. I was in the hvac business years back and we installed metal size being diminished the farther away from the unit, never had a complaint round air flow helps the room receive good flow.
Round ducts have a static in general. However, there are tons of houses with square duct that’s sized property with no issues. Sounds like your issues are more with sizing and less about static at this point.
Fan may need to be looked at.
An HVAC contractor did a load calculation for my house and determined the cooling need to be 35,674 BTUs. The 2-stage A/C I was considering comes in a 36K (3 ton) and a 48K (4 ton) size. He recommended the 4 ton to be sure there was ample capacity. Do I risk over-sizing my unit (my current unit is 4 ton). Other option is their 1-stage and less expensive A/C does come in a 42K (3.5 ton) size. Would this be the better option?
What are your thoughts on running a manual J heat load clac before installing a HVAC system? Almost every HVAC contractor I got quotes from never ran a manual J and would just look at my house, the old unit, and eye it. With no evaluations of the renovations and changes the house went through over its lifetime, including some duct work changes. Most just wanted to replace with the same tonnage but one tried to upsized my system because he "felt it was needed" but didn't run any calcs, which was madness to me since the house had windows and insulation upgrades over its lifetime. This was for single stage heat pump quotes.
I would request one even if you have to pay for it
I'm in Maryland in a 2.5 story 1800 sq. ft. drafty stone home built in the 1840's. The primary heat is radiant and I have a 2.5 Ton system that was installed in 1997 that is rusting out. I've had two estimates for a ac and heat pump system in the past two days. One for $8800 for a 2 Ton Carrier system and one for $7500 for a 2.5 Ton Goodman system. The guy that spec'd the 2 ton said that the 2 ton is plenty and I could go to a 1.5. The other guy said he would prefer to put in a larger 3 ton in but because of the limited space he would have to put in a 2.5 ton. Two questions, one are these prices reasonable and two which system sounds more appropriate for my situation. Thanks
Every market is different. So I cannot say whether their prices are good or bad. That said, it sounds like you should have a company do a proper heat load calculation to find out what size system you actually need. Depending on how long you’ve lived there, you will know if the 2.5 ton system was at least big enough to handle your home.
I live in md( silver spring) I also have a smaller house but I'm getting a 3 ton only because that's what's in the house now. My quotes are both 3 ton 2 stage heat pump+air handler. 7k for both lennox and bryant two different contractors.
Awesome! I used to live in College Park once upon a time
You can Google what heat pump should for my whatever sq ft house.
No that stuff isn’t as accurate as a proper heat load calculation
Having issues with an oversized central AC in Minnesota. System was short cycling on and off every 5 minutes in moderate heat. Replacing the original round Honeywell mercury thermostat with the new Honeywell round non-mercury thermostat helped. We also added a delay on break timer to the condensing unit, and set it for 10 minutes. The temperature needs to be set to 66 degrees to get adequate humidity removal. With the new thermostat and timer, we get about 3 on and off cycles per hour, vs 6 to 7 cycles per hour before the modifications. Sometimes the air handler comes on in 8 minutes, but the condenser is held off for a full 10 minutes. The house is much more comfortable, and we are attempting to save wear and tear on the condensing unit by avoiding excessive on and off cycles. Is this reasonable or would you have done things differently?
There’s things you can do to help like adjusting air flow but why is it oversized? Maybe you should get it sized properly and go from there?
It is a 2 story house, 1960's construction with 4" duct work. The upstairs was always hard to cool, so the contractor installed an oversized unit. The thermostat is on the 1st floor, and it cools very fast making the condenser shut off. The 2nd floor gets even less AC now. With the stat set at 66 degrees, I can get the second floor down to 72. The finished basement runs 62 degrees. The constant short cycling was disturbing. The replacement of the stat, and the addition of the 10 minute delay on break timer in the condenser solved that issue to some extent. I don't want to spend more replacing this with a smaller unit. I just want to make it the best it can be.
@@chipmaster56 Sounds like better off with a 2 stage system so it can run at full power to cool off the house at first and then run it half power just to maintain temperature.
I am in Austin, I’m building a 3000sf airtight house with spray foam top to bottom and at least two coats of ecoating on windows. 3 if they face east or west. I am told I need at least 5 ton. I want variable speed but think I risk a lot if I don’t add a whole house dehumidifier no matter what size I get (and feel 5 ton is overkill with the energy efficiency.)
Yes sir, 5 ton is overkill! A 4 ton will work much better, run longer to reduce humidity.
@@jimdavis9581 we actually ended up putting in a mini split into the room that has all the solar equipment. Probably the biggest pole on the energy is the humidifier since we built in winter and built quickly. That will settle down soon, but it’s 106° today and we are comfy!we actually ended up putting in 3 1/2 ton and another mini split also in a bedroom on the west side because it would get a little toasty late in the day. Strikes a perfect balance.
Also, it’s a Daikin fit inverter unit so it’s kind of always running a little bit. But anyone who says you don’t need a dehumidifier in new construction with spray foam doesn’t live in Texas.
Heat rejection is a big thing, lots of post and beam houses have no roof insulation or attic. How do you account for this when speccing a HVAC system?
Depends on the house. Sizing correctly would be paramount, but installing everything to avoid stale air pockets and proper circulation is a challenge in some homes.
Is 2.5 ton vs 3 ton a big difference for a/c in the northeast?
my house has a 3.5 ton heat pump which was builder installed in 2014. Now i need to replace it and one of my HVAC contractors conducted a thorough heat load calculation and told me i need a 3 ton pump instead of 3.5 ton. The area he measured was 1847 sq ft that the pump had to heat and cool. He said he would sell me a 3.5 ton if i wanted it but i dont need one that big. I just want what i need and his calculations were so detailed and we went over it in such detail that i feel i should go with the 3 ton. Looking at a Daiken Fit 17 seer with a 12 year warranty. Does the 3ton pump sound right to you? He also showed me how our builder had screwed up our duct work sizing and will fix that as part of install. Any thoughts on my going with the 3 ton unit? You do great and educational videos.!!!
The confusion lies in multi speed systems. For example 2000 sq feet for heat basic number is 80000 btu of heat based on 40 btu per sq foot. So if it is a 2 stage system i would size the heater at a 80,000/60,000 for an example. The problem is there is nothing comparable on the AC side coming from manufacturers when in comes to high seer multispeed compressors and hvac systems. In western Colorado desert climate witj average temps around 95 snd arid you can oversizeba system and it will run largely at the lower speed most of the time but on those days when it 105 the system can operate at 100 percent, not run all day and it gives more flexibility. So now that i say all of this i am a layman learned hvac in the navy working on aircraft. Have done a number of installs for family and myself and i am wondering if my logic is correct on both heating and air? Seemed to me once i did the cfm calculations for duct sizing and matched the blower speed to the system requirements to the whole house i felt pretty darn confident i had sized the unit correctly and checking my temps and gages on ac obviously to see i was operating correctly.
More than one way to skin a cat but e size the system, then ductwork, and then measure for each room. I feel that’s how most pros do it that I’ve been around.
Yeah the recommendations that I got from 5 out of 6 HVAC contractors in my area when i was looking to upgrade my system where I live it is always best to oversize just a little bit. True most people only need a 4 ton system but sometimes they need the power of a 5-ton system in the summer the solution that was given to me was to install either a two stage or variable speed 5 ton system depending on where a person lives this is a perfect solution. Where I live in deep Southern Arkansas the calculations say I need a 4.2 ton system but since there's no such thing as a 4.2 they automatically downsize to a 4 ton. Which yes true that works perfectly good in the spring and fall when the temperatures are in the mild 70's and 80's but in the middle of summer around June, July, August and maybe some of September when we are getting triple digits or high 90° temps my single stage 4 ton system ran constantly and could barely maintain 78° and would actually climb into the mid 80s in the middle hottest part of the day, which in my opinion a lot of people recommend setting your thermostat at that temperature but yeah nah I'm sorry that is way too warm for my taste to be comfortable so the solution recommended to me was a two-stage 5-ton system or a variable speed 5 ton system with a variable speed blower with a TXV and voila super long run times with 0% humidity removal due to an undersized system solved immediately. It easily gets the temperature down to where it's set quickly and then maintains it with the lower 70% which im told is roughly a 3.5 to 4 ton capacity. Which is sufficient enough 95% out of the year. My electric bills went from close to $800 a month on a 4 ton single stage system to barely $250 with a two-stage 5-ton system because so far this summer it has rarely ran in that second stage resulting in lower energy bills. Most HVAC contractors say "no don't do that it is a bad idea" but people got to remember they've got to make money too so common practice is the undersize you little bit so your system struggles when it's super hot and it breaks down quicker because it constantly runs 24/7 instead of cycling normally.
@@Brad.W Yep. Our 30+ year old 2 ton single stage AC unit was struggling to keep the second floor cool so we recently purchased a 3 ton 2 stage system for both the AC and heater which helped us to get through the triple digit heat wave here in California recently. We have noticed our electric bills for cooling have gone way down. So make sense to replace the aging AC system with a more efficient model. Expensive to get this thing installed but in the long run our lower electric bills will show for it.
Looking for new heaters and new ac for a brick duplex in Phila. One contractor said my ducts would only handle 1 1/2 ton. Another said he would put in a 3 ton upstairs and a 2 ton down stairs….because of the poor insulation and hot sun on the brick. Who am I to believe?
I had to buy a 4 ton system for my upstairs that is 1500 sqft inverter system, due to my cooling demands because my house is in full sun all day, large amount of windows and I have a server rack and electriconics I have. Every hvac guy would only size the system to sqft, and not by device heat wattage either or they wanted to replace with 2.5 ton that was there that wasn't keeping up even in the summer with out the electronics and server rack running.
Sizing should never be base on sq. feet. It should be based on heat load as you indicated. Yes, you need that 4 ton due to the increased cooling demand from those large windows and electronics.
What is a high seer unit that does not heat also? I live in Bali and it never gets cold.
You answered all my questions. Very good video. 👍
Great Video ! Question what happens if my contractor sizes my air conditioner by rule of thumb(sq ft only) instead of doing a proper load calculation
Thanks!
@@NewHVACGuide again Question what happens if my contractor sizes my air conditioner by rule of thumb(sq ft only) instead of doing a proper load calculation?
Lots of things can happen. For starters, systems can be less efficient. Your comfort level is reduced. And you can have issues with humidity in your home.
@@emreyurttas5051 find a company that does
Hi Josh. For 20 years I had a 15 SEER air conditioner out side, with a 2.5 ton blower in the attic. I could keep the thermostat at 75 and the unit did a great job of getting the humidity out of the house, so it was extremely comfortable. When that unit went bad, the technician replaced the air conditioner with a 17 SEER heat pump and 3.5 ton. I feel like it gets too cold too fast, so it doesn't run long enough and the house feels humid. I tried a few things...
I lowered the temperature to around 72, which keeps the house at 70... less humid, but a little on the cold side. Then I tried putting the temperature back up, but closed the dampers a little on the vents in the room with the thermostat. I thought maybe they were blowing on the thermostat, causing it to shut off sooner. I think that helped a little but it was tough getting them just right. Then, just as a test, I taped a sheet of printer paper over the thermostat to see if blocking the air hitting it directly made a difference. I think that worked great. I'm wondering if maybe just putting a thermostat cover over the thermostat would do the trick? Any thoughts?
Probably not. Thermostat needs to be located near the air return away from sources that could interfere. A dehumidifier can help in your situation but RIP your wallet in electrical bills
Air on thermostats... ugh! My A/C cuts on and off too much on hot afternoons, so I checked the thermostat calibration. The temperature of the wall 3" from the thermostat was 76F, exactly as the display showed. The temperature of the thermostat screen itself, 80F!. Stupid LCD screen is producing heat! I experimented with a small fan blowing on the thermostat, and my A/C wouldn't cut on until it got 80F! I guess my thermostat has a 4F compensation for the hot screen. So the fan made things worse.
What causes banging in the basement.. I assume from the duct work expanding and contracting.
Did I miss where you tell us about how to size?
I installed my own HVAC system this year central air worked great maybe a dumb question but the blower runs harder when the furnace runs than when the ac is on is this due to the ECM motor
Yes
@@NewHVACGuide my local gas company moved my gas meter from my basement to the outside they checked for gas leaks and noticed new furnace and central air system he said who installed the system did a nice job I said thank you lol
One thing to consider I've heard concerning ductwork size is concerning air filters. AC techs where I live don't recommend using these "HEPA filters, as it restricts airflow and the blower motor has to work much harder.
Some filters do add way too much static. Check out my video on air filter comparisons
Can u have a 3 ton outside and a 3.5 ton air handler inside
Yes
I got an estimate on a split unit
No one else suggested that but this one company
So I’m not sure if this is a good idea to do
@@DR-xt9ux just make sure it’s an AHRI match.
@@NewHVACGuide ok thank you
What about cooling a 50sq ft area? Any good mini splits or inverter window units? They all are about 5000 btu's, which seems to be oversized
I'm trying to figure out what size minisplit system I need. 99% for cooling for 680sqft(living great room/dining room and half of kitchen including range/oven). About a half of the area is 8ft ceilings(kitchen/dining room) and the rest range from 8 -15ft angled ceiling. According to strictly square footage, a 18k BTU system would work. Should I upsize one notch because of the ceiling height and partial kitchen?
Too many variables to answer this question pal. A unit can cause issues if it is oversized. Have your contractor do a Hilo calculation before purchasing the unit
I moved into a brand new house six years ago. The people that remolded house but in a furnace that is to big so it shuts off when duct gets to hot. Can I cut into duct to let heat out? Thanks
I don’t know why not 🙂
What have you seen with the reliability of an inverter heat pump vs just a two stage? The first seems to have higher efficiency, but is there an increased rate of failure? The higher cost doesn't bother me so much as the potentially higher repair costs down the line. If that is covered in your guide, I don't have a problem getting it now. I'm not in the market, but my units are old, so I could be, unexpectedly.
I don’t think they have a higher rate of failure. Since they are inverter systems, they work less hard at times. The only thing we have seen in across-the-board with all systems including inverter, multi stage, and single stage is the cost of variable speed blower motors has increased way more than what PSC motors used to be.
@@NewHVACGuide Thanks, I appreciate it. Not knowing any better, my initial thought was more complicated, more chance for failure.
They certainly have more bells and whistles. Air quotes “ more things that can go wrong“
But pretty soon I think they will be all you can buy anyway. So folks need to get with the program LOL
@@TheEngineerd Inverter systems are more intricate with a higher level of control, however due to this higher level control the complexity of the electrical components within the unit equate to more expensive repair costs because unlike a regular air conditioner that has a very basic and simple set of components that operate the unit, the inverter systems typically take longer to diagnose properly, which can start to add up on a bill real fast and when the unit is diagnosed to have a faulty control board, or some other part that is specific to that unit, it can cost a lot more for the parts due to the fact that you must install the OEM part from the manufacturer otherwise the unit will not work. And most of the time when units have brand specific controls that are only used on that one piece of equipment, the price for these parts is unreasonably expensive. A traditional AC unit contains parts that every single tech has on their van that are much less expensive and are easily obtained at any supply house. With higher levels of control come higher cost for repair, labor,and longer downtime due to the fact that a lot times these OEM parts need to be ordered and shipped instead of being available at all supply houses. I think it's wonderful that these systems exist and they have their benefits per application but I value reliability, consistency, and simplicity over a small increase in energy efficiency. This does not mean that I dislike inverter systems it just means I do not prefer them. That is my genuine, honest, and sincere opinion.
Night tone - all good points-I’ve had all three in various houses- that old single stage unit juts chugged along for 22 years, gradually grinding itself to death . Noisy, inefficient, but it was sized ok and didn’t cycle that much, but it was noisy !. Parts were cheap always available etc. then moved to two stage unit-more comfortable in one house, but because it was more efficient higher seer and we mindlessly just used same tonnage, a lot of cycling- why? Lowest it could ramp down was 40%…..more repairs. More recently we Et with full inverter and variable speed ecm fan-expensive but way way way more comfortable - not even close, and critical in humid tepid days in fall and spring. As Ana side I’ve had trane, carrier /Bryant and Lennox, American standard, all are good, -look for the form and look for the actual ethos who do install/repairs, not the owner .you don’t want too big a form-they have huge staffing issues these days-i prefer smaller firms who can retain and train staff. You do run risk they may run into problems if owner retries, does, one staff guy retires, moves etc, but as long as you have a brand that has good distributor in your area, parts available, and many dealers to choose from. You arce good. Equipment wise, I think Lennox gets top billing- very sophisticated and well built and thier communicating thermostats the easier to pe rate and very stable. bUT Lennox insist you only move their products and in most fewer dealers. Carrier overcharges, but in almost any jurisdiction parts are widely available, many forms service so u can lick or chose if one firm lets you down. I just hear more complaints about parts and issues with the than the others and it’s pricing it’s certainly no better. Lennox had some big manufacturing issues about a decade ago but addressed quickly and things seem smooth right now. NB if going with top of the line heat pumps, only carrier/Bryant have heated dehumidification, very valuable if you have long trunk seasons , ie lots humidity, temps I. The 70’s. NB hvac these days is very complicated, most techs are in over the heads, the young ones due to experience, the older because they haven’t kept pace with technology.
just had a thought on what you said, if you have a AC unit that's over kill but have a over kill dehumidifier, would you or would you not use less electricity of course being properly insulated.
I think it depends on the situation. I was just saying generally that a dehumidifier cannot be oversized because it will just reach the humidity if oversized and then turn it off
Well good stuff but sometimes the el cheep o is all some can afford and at the price I have in my inverter splits , I can throw away one a year for the first 4 years and still come in at a better deal, but now if the some of those top tier mini splits would come down some in cost it would be something
Would over size by 1/2 ton be a problem?
So say if i opened the windows of my room will my oversized ac becomes normal?
So how do you combat those super hot days that happen 10-14 days a year ? A “properly” sized unit will leave you hot on those days. We like to keep our house at 68 during the day and 64 at night.
Add a small mini split unit to you main living area and set in one or two degrees higher than your normal setpoint. It will add capacity when needed and be a backup If your large unit fails. You can get one under a grand.
Lots of words but no information. It's obvious, too large is bad, too small is bad. What is the proper size of a/c based on? What is the proper size of duct based on? Velocity mins/maxs? Air changes? Delta T?
Very informative video. Lots of quality information communicated in an easy to understand manner. I am renovating the second floor of my cape cod style home. Currently steam radiator for heat with window air conditioner units for cooling. Mold has been an issue due to lack of ventilation & increase indoor humidity due to steam heat. Located in NJ so humility in the summer months can also be high.
Looking to modernize our HVAC system during this renovation. Ductless system seem like a great technology innovation but concerned about the aesthetic appearance. Any recommendations for most visually appealing ductless systems?
Where in Nj?
Hi Joshua! Great video, very helpful - like all of your others. I have a ductwork sizing question. I got a couple heat load calculations done for my 2nd floor area as I shop for a new heat pump, and I've gotten estimates of 4+ tons needed. I've used 3 tons since I bought the home years ago, and am replacing the second floor heat pump. I would like to go to 4 tons because I've always felt 3 tons was at least slightly insufficient on the hottest and coldest days here in Portland, Oregon. Two bidders flat out said my ductwork supply lines were too undersized for 4 tons. I have 12 supply registers (6 inch pipes to each), and one rule of thumb quoted to me was approx. 100 CFM per register, and each ton needing approx. 400 cfm, leaving me 400 cfm short for 4 tons - way too short they said. I was going to go with a communicating variable speed heat pump and air handler (either Trane or Goodman), so felt like I did have some "cushion" against constant strain on the system. Your thoughts on this? Do you agree with the rules of thumb cited to me?
Variable speed systems do not remedy a duct sizing issue. Although forgiving, the systems will never operate efficiently if the ductwork is undersized.
Need advice,
I have a common 3 Ton split system gas furnace. My compressor failed after 15 years of service. I recently purchased a new 3.5 Ton heat pump condenser as a replacement. I would like to take advantage of the heat pump technology and use the gas furnace as backup heat. My question revolves around the specifications of the new replacement evaporator coil.
I noticed that most heat pump condenser units are married to an air handler with electric backup heat, instead of an evaporator coil box on a gas furnace. I understand that gas heat is possible as backup with a heat pump, but I'm confused about what modifications need to be made to the evaporator coil TXV.
Please advise if there are special TXV for heat pump evaporator coil configuration and if there is something that is needs to be done to the furnace.
Thanks
Kevin
Nothing special. Just needs to be set up like a normal dual fuel system
I'm having to add cooling into my 4yr old home because when built (not by me, model home) they way undersized the cooling. 3.5 ton 1st floor and a 1.5 ton 2nd floor units on a 2600 sq ft 2 story, with no trees. Oh yeah, in Houston lol. It seems that the AC industry in general always wants to use base load calculations and call it a day, at least around here thats what they do in residential and commercial.
Good video, I have a question. I have I have a metal garage 20'X12' 240 SF. It's all insulated with 1" foam except the garage roll up door. I want to install a mini split 9,000 BTU or 12,000 BTU?
Not an HVAC tech but personally, I'd go with 9K BTU. I'd also look into ways to insulate the roll-up door to avoid condensation. I'd try something like reflective bubble insulation. If this were a garage I only wanted conditioned occasionally, I'd go with 12K BTU to get it to temp quicker.
@@AvgDan Thanks for the info.
I'd have a proper heat load calculation done if comfort is an issue... There's more variables than just square footage.
Need at least 12,000 because of the door and only 1' foam won't do much.
Deffinatly go w 12000 and in that situation 12k may actually not be enough depending on your location. Always do a load calc. Insulate the garage door aswell like Dan suggested
The main problem is ductwork in the attic which is nuts. Ductwork should be in conditioned space in soffits or in an fully insulated attic.
It definitely has to work harder when they’re sitting in an oven (hot attic)
Does anyone know what size rectangular ducts are needed for a 420 square foot 3 room addition? It has a separate furnace, 24 foot straight run and six 6" side vents. I got 8" x 16" supply rectangular ducts but haven't installed them yet as I'm not sure if they aren't too big for heating.
I am trying to replace my hvac system. Heat pump. Old system is 2.5 tons but l want to upgrade to 3 tons. I am in Georgia. I want to know if it will be ok. I get 17 sq ft
Have a proper heat load calculation done even if you have to pay for it 🙂
Going bigger is not an upgrade. An upgrade is getting a better technology in the unit. Going bigger if it is not adequate the application will be a DOWNGRADE in efficiency, comfort, humidity control, longevity
Most systems are oversized and most contractors will oversized you
I have a 2 ton AC unit and I am replacing it with a 2.5 ton would that be OK or would that cause humidity issues? My townhouse is 1170 ft.²
I have about 1100 sq ft townhome on a lake with a direct west view in south Florida. We have lots of humidity here. Prior we had a 2.0 but I felt it wasn’t blowing enough or cooling the house down as good as it should. I talked with the HVAC person and he said 2.0 or 2.5 would be okay. The first day it took a while to bring down the humidity. Overnight it brought the humidity down from 65% to 53%. Thankfully. Phew. I thought we were screwed. We got a Bryant.
Awesome video! Quick question I live in Canada on the West Coast. My house is built in late 80s 2 storey home, We are looking to add Central AC to the main floor 1450 sqft (3 beds, kitchen, living, dining, hallway) one contractor said I would require a 2.5 ton one said 3 ton is it safe to go for 3 ton if I choose a dual-stage system to prevent cycling?
Well you’re only talking about 6000 BTUs. However, I would recommend having a proper heat load calculation done even if you have to pay for it
Please help !!! New 5200 sq ft first floor with a 500 sq ft bonus room above.Foam in attic and rockwool insulation in exterior walls. 2 Units 4 ton each for a total of 8 tons. living room 14 foot ceiling and all other rooms 12 foot. Does this size make sense? I would really appreciate any help on the question above....
Get a proper heat load calculation done even if you have to pay for it.
if anyone can help me out would be awsome or how to go about this
I am replacing a 2.5 heat pump and the house its 850sf
2 rooms one kitchen 2 bathrooms and 1 corridor , is it too big tho …
Get a proper heat load calculation by a pro even if you have to pay for it
I had the 25 year old unit in my parents home replace 7 years ago. The old 3 ton Lennox was a good workhorse but on normal 90-93 degree summer days it would run all day to maintain 75. On 95+ days or when the stove and oven are used a lot it would lose ground.
Their HVAC guy (same one who put in the old one) replaced it with a 3.5 ton Trane (still single stage)and what a difference. With the variable speed blower it dehumidifies better than the old one and they were able to raise the set temp to 77 because 75 felt colder than the old unit. On normal days it runs 15-20 minutes to maintain 77. Even at 75 it’s run time is 30-40 minutes on normal days. On the occasional 100+ days it runs for hours but has no problem maintaining 75; at a 77 set temp it would still cycle. Big drop in their utility bill as a result.
The contractor gave most of the credit to the variable speed blower’s ability to dehumidify by running a low speeds at startup and slowly ramping up, not the extra 1/2 ton. He said it’s not that much of a size difference and the the 3 ton running all day to maintain 75 is considered optimal performance. But the variable speed blower of the Trane makes it feel cooler. Also, he says Trane and some others are making larger condensers compared to older units with the same tonnage. Combined with the swept wing fan blades the Trane is able to dissipate heat better than the old Lennox and use less energy at the same time. Compared to their old Lennox the Trane is huge but ironically it’s refrigerant capacity is less than the old 3 ton.
I'm over here oversizing my home and looking to add a humidifier because it's so dry out here.
My house is 1100 sq ft with 7.5' ceilings and 111 years old. I live in SW Missouri with high heat and humidity. I am getting a heat pump split system Trane xr15 2.5 ton with an S9X1 furnace. Would a 2 ton system be better?
I’d defer to your local contractors’ opinions. If something seems off, get another opinion.
@@NewHVACGuide Thanks for responding. I used another calculator and entered my SW Missouri climate as "like Houston" and got 2.5 ton. The contractor was born and raised in my town, so I will trust him.
Nope. Old house that is not tight.
I live in Kansas. Getting ready to have hvac system replaced. Little over 1800 sq ft home with partially finished basement and 10-11ft vaulted ceilings on main level. Currently have a 3 ton system that is original to the home when built in 2003. Should I go with a 3.5 ton or stick with a 3 ton system? Our current ac has never worked great since we moved in 2016, but that could have been because it wasn't working properly, not necessarily because it's undersized. Thanks
Have someone do a proper heat load calculation even if you have to pay for it 🙂
You should have a ceiling fan in a house with high ceilings. This will help your comfort level. Make sure your house is insulated very well. 3 ton should be good. Oversized unit will waste money. Oversized units will cool the house quicker but will not dehumidify the air as much which is another thing you should want to do.
I live in a 3600 sq. ft. home in Arizona so it is hot. I have a 2 ton unit which covers my master bedroom, closet and bath and my 4 year old Lennox unit does not adequately cool. There are 2 vents (10 in vents) in master and it cools fine but the bathroom has a little 6 in vent and so does the closet and closet blows barely anything so it is stifling in there; and the bath is the same; just blows slightly more air. We had Lennox rep who installed system and they said it is working properly but it is miserable especially in summer. We have solar panels on our home and our bills are still over $200 a month and that is keeping our units at 78 during the day; even if you turn it down in the afternoon the thermostats will not reach 75 or 76. I am miserable. Our old trane units in a much larger home cooled within minutes? What to do? I am aware the builder uses units and not square footage and the air flow is not cool. It is a long summer here. Some neighbors have had to reduct ($2000) and had to order new larger units.
Wow. What a pickle. I recommend finding a good contractor local to you and going with what they recommend. Every market is different. So find someone awesome and go from there.
Thanks for sharing this, I live in East coast I have two storey house 2100 sq, I hired a contractor to install HVAC and recommend me putting 5 tone AC, I'm concerning if is to big for the size of house?
Have a contractor do a proper heat load calculation
Trying to get a new gas high efficiency furnace here in Massachusetts. My old one is a 96000 btu furnace with pvc flue. 2500 sq ft house , built in 1995. Why am I getting some companies say I need 80,000 BYU’s and some say 100,000.? Old one seems ok.
96k would be pretty much the same as a 100k if you're comparing.
2500 sq ft house built in 95 could very well only need a 60k, please have a manual j load calculation done. if 60k is a little small, look into lennox and rheem which offer furnaces in between 60 and 80. I'm in southern ontario canada, same kind of northeast winter climate and 80k condensing furnaces go into 3000-3500+ sq ft homes. It takes either a huge or very poorly insulated home to need 100k in northeast.
I live in bakersfield got a new house 1882sq ft and has 9'ceilings and has 11 windows plus sliding door and they installed a 2ton 24000 btu and we cant cool house down the coolest it has been is 78° in the morning but 86 around noon who will be responsible builder? inspector that passed it? hvac company? or am i going to have to eat it just not fair its a new house and is under warranty
How much BUT for 75 ³ m (5X5x3) to make it cool ?
No isolation
2 windows
The ceiling exposed to the sun
I recommend finding a good contractor local to you and going with what they recommend. Every market is different. So find someone awesome and go from there.
Then have a proper heat load calculation done even if you have to pay for it.
Im in Hampton Roads, VA. My place has a old 2.0 ton unit (from 2001) but it struggles (1800 sqft) on hot days it does hit thermostat temp. I had a quote from HVAC company to a 2.5 ton system and 2.5 vap coil. Should a 3.0 ton be used instead?
I recommend having a proper heat load calculation done even if you have to pay for it.
yes
3 ton for 1800 square feet
Thanks josh for cool vid. Im a new homeowner and put in a new system end of last summer. I have one zone duct. Gas Furnace and ac coil on too, in basement. Condenser is 5 ton, 16 sheer. 2k sq foot. Hard Ducts goes from basement to attic and branches out throughout the house. Problem im having now is in winter. Too hot upstairs & too cold down stairs. I tried resolving it with nest sensors. But downstairs is just weak. I even tried adjusting ceiling diffusers, still hot upstairs. Upstairs is all flex ducts from attic to second floor. Flex ducts looks quite big. Should i reduce the size of it?
I havent experience the summer yet with this system. I am assuming it will be hot upstairs and cooler downstairs?
So it’s one system supplying both floors?
Yes. :-(
Is it zoned?
No.
Watch this vid. You need zoning. th-cam.com/video/54G-K9X6S6U/w-d-xo.html
This video is incredibly helpful and informative.
We just ordered 2 Amana 311 seer 16 air conditioners for our 2 story high ceiling 2900 sq ft house. They arrived today and they are huge compared to our old air conditioners. Are you familiar with the model we got and do you think it’s too much?? I live in California btw
All systems today are like that, I had mine replaced about 7 months ago. I have a 5 Ton 19 seer Daikin Heat pump and it is much much bigger than my old 1994 5 ton York. They have to be large to meet efficiency standards and I dont know how old your last system was but if it was a R22 which is more efficient than R410 what is used today but R22 was bad for the Ozone.They need larger coils to remove the heat with R410 than they did with R22.
@@wes2460 Thank you for sharing. The old units were installed when the house was first built in 2005. But one of the units was making a thud sound when it turns on so now we are seeking to get a replacement. But nextgen is giving us a hard time
Good info, although a lot of these issues aren't really done by the contractor. Most of this would be taken care of by an HVAC designer/engineer not necessarily a technician or contractor unless they are partnered with one or are a full design build company. A lot of the time when I've had to redesign a home the issue is because the design was not followed by the original builder and residential codes are way more lax than commercial codes especially when it comes to duct work. Most duct work in residential is lower quality soft duct which usually a wire spiral frame with insulation and a cloth and plastic membrane vs spiral hard metal or square metal duct work wrapped insulation. Unit selection in high humidity usually has a hot gas reheat coil which warms cooled air back up strictly for humidity control or has a humidistat and variable refrigerant control to ramp down for steady air volume. These are required in commercial applications and not so much in residential. Over sizing tends to occur when installers dont follow schematic design or install things designers hate like 3 way duct splits which I personally despise as a designer. Another issue is duct runs over 100' due to static pressure loss. The fans in residential units just dont got the static and volume for that length. This could be due to roofers boxing out the wrong spot though and not the installers. All in all get youraelf a contractor who partners with an engineeer or a design build.company if you have major issues
I have a choice between lennox 2 stage heat pump or brysnt 2 stage heat pump, which should I go with? Thanks in advance
Tough choice. Which contractor do you like better?
@@NewHVACGuide One was recommended by father in law and the other by my friend lol. Don't really know either one. The friend of the father in law is 100 bucks cheaper. So he would install the lennox. Which brand has cheaper parts?
They are probably both about the same for parts. Both are a little on the higher end in our market
@@NewHVACGuide Thanks for your help. I guess I have to flip a coin lol
Honestly, if I were talking to my own family, I would probably tell you to go with the Bryant. But that’s just because I’ve had a few bad experiences with Lennox. However, I have friends that will only install Lennox and love them
I used the coolcalc website to do a manual j calculation; Using my address in San Antonio, TX, the "outside design conditions" temp range by default is between 31 and 96f. This results in a load calculation of about 36k btu for cooling. But, we regularly hit 100+ in the summer, sometimes reaching up to 110. If I put 110 as the high for the temp range it calculates around 47k for cooling.
Would we be better off getting a 4-ton unit to handle those hotter days or could it be too much for most of the time when it is below 100 and cause those humidity issues?
If it’s an inverter, it will ramp down on milder days.
You can only size it as large as the existing duct work allows. A general rule of thumb is 400cfm per ton. That is a VERY general rule of thumb. Size it properly with static pressures and either build new duct work or go with what the duct work will allow.
Agreed. In my experience though, way too few hvac techs "do" static pressures. @@brianbastianini4867
Thanks Josh. I'm in northern Virgina and am replacing my existing HVAC; 35 yr old single family home, around 1800 sf, new windows & siding. My current maintenance company proposed to replace my old 3-ton AC / 100-BTU (2 stage) furnace with the same sized equipment (AFUE is 80). For the second proposal, the contractor came to the house and said the current furnace was larger than I needed, and proposes to install a 3-ton AC / 80-BTU (2 stage) furnace (AFUE=80). The second guy was correct when he guessed that my current system probably didn't kick into stage 2 hardly at all in a normal winter. Any thoughts to share? Why should I go with the 100-BTU furnace if the second stage is rarely used?
We typically match a 3 ton system with an 80k btu furnace and have never had an issue. Did you ask the first company why they want to stay with the original size?
Never automatically assume you can replace like for like. The equipment you have now could be undersized, correct or oversized. When replacing, always do your own calculations for what size equipment to install, so you don't possibly repeat another's mistake.
David-wouldn’t you agree if youre system is cycling a lot in fall, spring, you can assume you are over sized ?
Josh- if you over size a Dehumidifier, won’t it cycle a lot and wast. Lot of energy because coil takes long time to get cold again when it re starts.
Good point
Great Advise Thank you!
Are very interesting I've been offered an air source heat pump , it came out of a friend's restaurant, it's an 8kw unit AOYG24LFCC, quite big as was thinking 3.5kw would be ok for my small house. Can this large unit run at the lower power? This machine was built in 2013
Have a local pro take a look. I’m not familiar with this brand
@@NewHVACGuide sorry should have said it was fujitsu heat pump. If I fit a large one will it run at a lower current , I see it's max is 16a , where I think 3kw was about half that. What steps do these run at?
I live in south Texas. My house is 840 sqft. 2 bedrooms. I got quoted a 3 ton. Is this the right size.
That would be big in our area. Maybe there is some thing more to the story like our ceilings for insulation issues. Have a proper Heat load calculation done and you will be good to go
Depends on when the home was built, how well is it sealed, are windows only single?
If you have an old crappy house and from 70s, yeah 3ton is pretty common in south texas. But if you have a newer home, say from 2015 or so. a 1.5 what you would likely need.
I just know my furnace is oversized for this house. It's 1321 sq ft, and the furnace is 80k btu. I set the fan speed to low, because the house can heat up so quickly at the fastest speed.
Probably shouldn't. Can crack the heat exchanger like that. Fast speeds need to be set properly.
Just changed my ac unit I had a 4 ton and it was struggling and my thought was bigger size and I got a 5 ton Goodman but now I’m realizing I made a huge mistake reading on it and kinda bummed 2000sq ft 2 story I’m in Houston it gets hot my 4 ton was old and it was on all day and night so my thought was in need a bigger unit the guy said okay what ever you want and now I’m stuck between what can I do? Add a dehumidifier but I did for the reason that my light bill was $500 I was like I need it replaced it ASAP then I did it the house is cold but now I’m thinking of solutions.. any thoughts? Just dehumidifier I read that I can add a duct to the garage to get rid of some and add a dehumidifier?
It’s against code to run ducts to your garage. Huge safety hazard.
That said, yes… Add a dehumidifier
@@NewHVACGuide best option would be to buy it again at 4 tons right? Man first home and I wanted to do something good but turns out it’s worst can I change just the outside unit add a uv light and dehumidifier? Or change both? He said the inside unit has low speed would that work?
@@eduardomedina4328 just make sure it’s an AHRI match but yes. Sometimes condensers are matched with larger indoor units for higher SEER ratings. And that would lower your capacity.
@@NewHVACGuide thanks! Happy 4th!
You too pal
I live in a 1,049 sq ft condo in Georgia that previously had a 2 ton regular A/C condenser and air handler/coil. Just had a company quote me a 1.5 ton Daikin DZ14SA0181 Heat Pump condenser with a 2 ton Goodman AWUF250816 air handler/coil. Does matching a 1.5 ton condenser with a 2 ton coil seem right? I was also originally interested in the Daikin Fit but they said it wouldn't work in my condo because the air handler I would need would be too big to fit in the utility closet. I was surprised they didn't make a wall hung air handler yet for the Fit. Also, thanks for all the videos you put out. I'm really learning a lot about HVAC and find it fascinating...
Hello! They do not make a closet air handler for the Fit unfortunately. It’s not uncommon for the indoor unit to be a little bigger than the outdoor unit. It just can’t be the other way around.
@@NewHVACGuide thanks so much for the info. Doing something like that won't void the Daikin warranty or anything? I just thought it was a little strange because out 6 different quotes I received they were the only ones who quoted a system that wasn't sized the same. Too bad they don't make a Fit closet unit, I would think that could be a huge market for them.
It shouldn’t void the warranty. You can ask for an AHRI certification to make sure they’re matching units and then you’ll know for sure.
@@NewHVACGuide Thanks...
3400 sq ft one zone home. 4 or 5 Tons?
Manual J 🙂
Thanks !
Nice informative video. Have a question, I live in the Midwest and could get really hot and humid in the summer. My house in the main floor is around 2000 sq ft. My unit is a 3 ton ac/furnace 2 stage. It working good except for one room that has a cathedral ceiling, I am guessing 15 ft high. Only one register but no return. It gets really hot in the summer. I cut off the bottom of the door but still really hot in the afternoon. My question is do I need a return vent or supply vent, or both? The room is comfortable in the winter. Thank you.
Every house is different, so it's hard to say. I'd recommend getting a couple opinions from your local pros.
check insulation above vault. need more diffusers.
This is helpful. Thanks. Wish you worked Montgomery Co in MD.
I used to live in College Park years ago!
Is Goodman a good brand
Check out my video on Goodman 🙂
nope
Goodman is the cheapest you can get along with a couple others.
Nothing cheapest in anything is good and worth having
Reasons to buy it:
Selling home
Rental property that will be sold in less than 10 years
Flipping home
Can’t afford anything else
Sizing isn't my concern. What I find is this Carrier unit. It's small. 9,000 BTU. But they call it 42 SEER... I don't believe it. Are they just making up numbers? For my application, I need all the efficiency I can get. It's not a matter of cost. It's a matter of being utterly impossible if it uses too many watts. It's not a matter of "being worth it." It's a matter of "it can't be done unless it's silly-levels of efficiency." Which makes me a perfect target for made-up numbers...
Ask for an AHRI certificate to get the true SEER
The number one thought for me, you don't make cold, you remove heat. Keep coils, FILTERS and duct work clean. It won't matter what you have if it is clogged.
I have to disagree with oversizing heating equipment. For one, if you heat a spade too quickly it’s super uncomfortable. Also, depending on how oversized the equipment is, a gas furnace for example, it could cause premature failure of the heat exchanger and premature failure of the blower motor as well as inducer motor. Not to mention persistent tripping of safety limits.
I think in most cases those issues would only happen if the system is oversized and the ductwork is not. But if everything is sized correctly as far as the ductwork goes, you would just have a system that short cycles a lot
@@NewHVACGuide 9/10 if system is oversized then ductwork would be undersized. I’m not talking about a 60kBTU furnace where there should be a 40… but definitely a 80 where there should be 40 or 100 where there should be 40. Also with it heating the space quickly like that it will be very uncomfortable and a lot of hot and cold spots/areas throughout home
@@timrob0420 9/10 houses, the ductwork is undersized anyway lol
@@NewHVACGuide lol obviously you’re not up in the PNW. Ductwork is jacked up here man
By the way, it takes 144 BTUs to melt one pound of ice in one day (24 hours). If you have 2000 pounds of ice (a ton) it is 288,000 BTUs absorbed to melt that ton in one day. If you divide that by 24 hours, 288,000 BUTs per day/24 = 12,000 BTUs per hours per ton. So a ton of cooling is 12,000 BTUs over an hour. PSA announcement. lol!
Call me crazy but I guess this means if you have a 1 ton AC unit, in one hour it will cool by 12,000 BTUs.
Hoping to pick your brain.
I have a 100,000 (input) btu 80% Gas furnace in my 2 story home that is 2500 sq. ft. but there’s a 3 ton AC unit here as well but both units do great heating and cooling all season(s). Since this furnace specs are 5ton, 2000 cfm ECM motor, should my fan be set at 1200 cfm for the cooling speed? I realize the AC is undersized for whatever reason but it works great. Anything here that you would see as being an issue?
Thank you for your time.
My electricity bills more than doubled during summer
the inside temperatures in the 80s despite AC being on 72 no one can find anything wrong. The third AC guy thinks it might be undersized.
However I'm getting tired of hearing the word I think
when I had the AC installed 8 years ago the guy wasn't sure if I needed a 2-ton or a 2.5.
so the phrase "I think 'is costing me money.
I'm uncertain how accurate a BTU calculator is.
I've used two different ones
suggest my house should be a 3.3 ton with 9 ft ceilings ,however my living room goes up to 14 ft and I'm not sure how to add in ..
If that living room ceiling would put me closer to a three and a half or not.
1232sq ,heat zone 1 , zero shade, the living room and kitchen ceiling goes up to 14 ft
So I'm not sure what to go with at this point the other guy informed he thinks I need a 3 ton. However with every calculator showing 3.3 not calculating the higher ceiling
I'm not sure which AC guy to go with at this point one says I need a three another says a three and a half
I'm meeting with a sales rep for our local HVAC provider. Mon Jan 29th. They will be providing me with an estimate. If I purchase the
$ 300.00 service provided by your website/service will you or one of your colleagues. be able to review the estimate and offer me guidance. I am completely in the dark here. We are replacing a heat pump with a 2-stage capacity. I'm located in NC. I also intend to go through your site to arrange financing. We are receiving some money from our Homeshield warranty.
If it is too hot, the occupant will turn off the heat. lol