Well, this rule of thumb should work on most applications. AC units are predesigned for certain areas of the country. Doing the heat load calculation is the best way to figure out what you really need. As far as a profit margin per ton, the larger the unit doesn't mean more profit. But the price can go up for the SEER rating and what extra items you get with your system. Most contractors put more profit on the medium SEER rating. They call it, Good, Better, Best. Financing plays a big part in this also. The biggest issue coming up soon, the changing of the freon, also they want to eliminate all gas furnaces and package units. In California people pay hidden cost for gas furnaces and package units. Just for general knowledge, the manufacturer raises prices every 4 months. That's why prices have increased so much, inflation.

Never go off of Sq Ft. Use a manual J load calculation and size it properly. I install in Oklahoma and most houses require about 1 ton per 400sq ft. It's better to oversize (with supporting ductwork) using a multistage or variable system rather than under sizing and running 100% all the time. Using multi staging or variable systems will allow the system to dehumidify and cool properly. But if you are using a professional to do your install, demand a manual J load calculation and do it right!

@jerryhuff86

5 ай бұрын

Yes yes yes 😊

@turtledunkknucklebaby8089

Ай бұрын

I just had an AC system replaced here in OK. I know nothing about hvac so I called a company. But it’s 1,050 sq ft house. The old unit was a 3 ton. They replaced it and the coil. The unit is a Amana 15.3 seer which ran 4,400, the coil was 2500 the total cost of install was 9400. I think they overcharged me, but I didn’t have time to mess around attempting to get multiple quotes from different places. A lot of places won’t even offer a free quote. Seems over priced just based on what Google “experts” claim the costs should be.

@witzviewer

Ай бұрын

How does a two story effect sizing versus a single story home? How do you properly size the system if you have separate ductwork for upstairs and downstairs, as well as two separate units?

@jcarney1987

Ай бұрын

@@witzviewer do a manual j calculation with 2 zones on separate systems. Also this is where multistage and variable systems really help out as well.

@watchmanspector1642

15 күн бұрын

Old school used to be 400 sq. ft. per ton - our manual j calcs normally say at least 900 sq ft per ton, and they have never been wrong. Glass and insulation are huge factors

Shade from trees also plays into it

@nostradamus7648

2 ай бұрын

What about shade from Marijuana bushes?

@MK-vc4uc

2 ай бұрын

@@nostradamus7648 LOL

The takeaway here is, if you are in the market for an A/C system or soon will be, do what you can to improve the insulation and air sealing of your home first. You will then have a double benefit, where you can buy a smaller, less expensive A/C AND spend less on electricity to run it.

IDK this installer, but I am impressed with the candid openness. If I lived in that area, I would buy from this vendor.

Thanks for the video and the chance to get a rough idea how big a unit a house needs.

SEER rating does save money, I did it in my own home is I would know for sure.

Could you please do a video on selecting the correct size AC units with split system install for both larger one story and two story homes

In the caribbean we use a rule of thumb of 300 sf to 350 sf per tone and that is for residencial. Now proper insulation makes a difference of course.

Relative humidity is a very important part of the formula. A unit's sizing could be drastically different when living in Arizona, or on the Florida Gulf Coast.

@Balticblue93

Жыл бұрын

100% agree with this comment. RH is huge in factors and latent numbers in your math.

@rodgraff1782

Жыл бұрын

@@Balticblue93 very true. You’ve got to get rid of all that latent heat before you can do much with sensible. In some areas, humidity is most of the load. Systems that are oversize will not dehumidify properly, because they are always short cycling

@Balticblue93

Жыл бұрын

@@rodgraff1782 Here is Denver, our math is the opposite. We need to figure how much humidity we can actually bring in. I recently read we are more arid than Arizona. I fight for every ounce of humidity I can grab.

@bobboscarato1313

Жыл бұрын

@@Balticblue93 You may want to consider a whole house humidifier!

@Balticblue93

Жыл бұрын

@@bobboscarato1313 And I think you do not have the entire story. I am an HVAC Engineer and specialize in Home Performance. Every single home / customer I deal with gets a whole-home AprilAire humidifier and filtration system with their new systems or I add them as part of their service contract. We run humidifiers all year round in the Denver 3/4 of the state of Colorado. I think I have that covered Bob. But I appreciate your input. The AprilAire 700 Automatic or 800 are not optional on my change-outs being that the healthiest air is 40%-55% humidity in a home.

Its volume !! Im surprised you didnt mention variable of ceiling height

I live in Abilene, TX. Too bad you are too far away to help us with our HVAC issues. You seem to be knowledgeable and honest. I enjoy watching you videos. I've added it to my DIY Mini-Split project knowledge base.

I really like those two pictures hanging behind him.

I'm 2/3 of the way through the video and I'm already stuck on the thought "just enough information to be dangerous" I wish life were simple but if you really want good performance and efficiency forget you ever saw this video. As far as sizing goes you need to talk to a contractor that is willing to do a detailed manual J heat load calculation. PS- equipment sizing and brand are SOME components of a more complex evaluation of the cost to the homeowner. Look for quality first then price second. Good luck everybody!

@LeanHVAC

Жыл бұрын

Most accurate comment.

@Beastphilosophy

Жыл бұрын

His method is technically wrong, but his chart produces the same result for my house as my meticulously done Wrightsoft. However given the cost of an HVAC system, it's so much better to do things the right way.

@HeatGeek1

Жыл бұрын

@@Beastphilosophy I would say his "chart" is more than technically wrong, I would say it's fundamentally wrong. Math questions deserve math answers. That chart is a fairytale. People tend to simplify things they don't understand.

@TimB-

Жыл бұрын

I'm late to the party, but totally agree on the manual j. However, finding any contractor that wants to run one is extremely difficult. Had 5 quotes for our system, none of the contractors completed a manual j. Closest they got was a total return grill calc, with no consideration to return duct volume (four of six returns share the same duct). 2 returned the answer to go with the size that was already installed. 2 dropped the furnace size by 20%. The last one asked me how our comfort was, how the system operated, and then asked what size I wanted. Gave him the calc I had completed and he said no one does the calcs as they aren't worth the time. Went with his bid, which still up sized from the calc. Ended with a unit 40% smaller output then what was installed. System has seen temps over and under design, still cycles on the extremes. Playing it safe or padding bids with larger equipment is not necessary. The math works. It is better to leave a customer impressed in one's expertise, rather than questioning one's competency.

@HeatGeek1

Жыл бұрын

@@TimB- I just wanted to add my two cents Tim. I'll give you full credit for wanting to do things better. Just one bit of insider perspective from a contractor who does do manual J load calcs. I only do my detailed manual j and other engineering design work after the customer has committed to me doing the work. It's far too much time and experience that would be spent on a customer that ultimately doesn't pick you. I will also note that I've been fond of telling people that not all manual j calculations are created equal. If you did get a contractor to do a manual j before you give the go-ahead to do the job it would be a very sloppy low-end quality piece of work.

Perform an ACCA Manual J block load analysis followed by Manual S equipment selection guidance or you're simply guessing! There are SO many other factors than simply square footage and climate zone. Oversizing an AC unit is the worst thing you can do!

In ew york tri-state area the installers usually calculate 400 sq feet per ton, not 500. Plus the ceiling height, plus big windows and south side and etc.

I remember back when Sears sold furnaces and A/Cs there used to be a gag thing going around about how the Sears salesman sized them. Basically it was a piece of cardboard with 3 square holes cut in them. You'd stand at the curb, look through the holes and if the house fit in the smallest hole it was 2 1/2 ton, the medium hole was 3 ton and the large hole was 3 1/2 ton. You could also use it to size the furnace, 75,000 BTU, 100,000 BTU, 125,000 BTU respectively. I have a 3 ton Condenser with a 3 1/2 ton evap coil which gives you better dehumidification because with more coil area it pulls more humidity out of the air per cooling cycle.

@TheMinecraftACMan

22 күн бұрын

Running a mismatched system with a 3 ton condenser on a 3.5 ton evaporator does not actually have any effect whatsoever on dehumidification, assuming you've correctly set your airflow for the tonnage. It has a slight energy efficiency benefit, as the small amount of extra surface area allows you to run a marginally higher coil temperature while still pulling the same amount of heat from the air. But at the end of the day, 3 tons of capacity is still 3 tons of capacity. Provided the airflow is set correctly, you're going to get the same amount of dehumidification out of either coil.

I’ve got a 2,300 sq ft 2 story home I’m Arizona, built in 2007 with two AC units (upstairs and downstairs). Had one AC contractor trying to sell me two 3.5 ton units but seeing this video I’m thinking maybe they’re overselling me? Current units are 2.5 tons each and that has worked generally well. Thanks for the video!

LOVE the inclusion of a manual J (or heat load calculation)! Size your units properly and your house will thank you

@JohnCap523

9 ай бұрын

So will your checkbook

in the south, when you figure out the size, then double it for the humidity

Thanks for help 🤙🕊🕊🕊

What you overlooked here which is most important is when the house was built. Homes today are built very tight an energy efficient. A 2000 square foot home built 30 years ago would require a 4 ton unit. A new home, same size and area will only require a 3 ton unit to work efficiently. Rule of thumb is generally 1 ton for every 500 square feet on an older home and 1 ton for every 700 square feet on a new home.

@bobboscarato1313

Жыл бұрын

I will use a 3 1/2 ton unit; no less!

@kenthomas4668

10 ай бұрын

Not even close. The new house being built around Chicago are way smaller ac than 700 square feet per ton way smaller! I do manual j's and they are all different no rule of thumbs allowed!

@shawnsg

9 ай бұрын

You didn't watch the video did you?

Two things, first it is the starting and stopping that wears out an a/c, longer runtime equates to longer life expectancy. Second, it's not what zone you live in, it's how the home was constructed. You wouldn't put the same size system in a home built 50 years ago as the same size home built 10 years ago. Do a load calculation on the home and size to that. By the way sir, NCI, National Comfort Institute, has excellent classes that teach just that, take one, please!

@fattysgarage1754

11 ай бұрын

This is 100% correct. If I up sized my unit, it would short cycle and my humidity would be off the charts. 1884 under air and 3 ton unit works well in sw Florida. Home built in 1998. It will run all day in the summer when temps are above about 90 degrees.

I live in a single story home 1270sq ft with vaulted ceiling living room/ dining room . Zone2. 2 ton or 2.5 ton. Currently 2ton unit 25 years and can’t keep up when 93 degrees outside

Here is a quick formula to figure what size a home needs. This was passed onto me by the smartest HVAC engineer I’ve ever known. I will say this; that a heat/cool load manual J is the best method. With that said a quick guess can be figured by this simple formula. The home volume x one of these three multipliers, 2.6, 2.8 or 3.0. 2.6 multiplier is for modern well insulated homes. 2.8 for your average 80’s insulated home. 3.0 for older poorly insulated homes with single pane windows. Sounds crazy but it’s remarkably pretty accurate when compared to a load calc.

@oaouda

Жыл бұрын

@Chris Moody, what is the units for the home volume for the that formula? For example for 11310 cubic feet what will be the heat/cool load manual J is for modern well insulated home? Thanks

@nram1

9 ай бұрын

What's missing here. I have 39,000. What next?

@Clamjammer

8 ай бұрын

@@nram1dived by 12,000

@nram1

8 ай бұрын

@@Clamjammer Thanks. I need 3.5 ton

After 35 yrs here In fl for the ideal sq ft is 500 ft per ton for a block home . If you have vaulted or high cielings adding 1/2 ton wouldnt hurt . A wood frame house that is raised with old windows i use 400 ft per ton . I have never had a home complain unit is not cooling properly . If you go oversized add a thermostat with humidity control

i got a system size for the house like explain in this video, when it was 104 outside the system will continue to run and will not drop the indoor temp below. 80. had company come out that installed it, would say the system performing as it should. it was under sized when in USE but on paper it was correct size.

When I purchased my new home, they had Put in 3 new units. Home size over 3K, I questioned the servicer he said 2 units would be hard for the home, house built in 2001.

HVAC tech here. Most companies in my area size their equipment wrong.

Thanks

Interesting thoughts. We discussed square footage when replacing the furnace and I had to argue with them that CUBIC ft is the proper analysis. 10 ft ceilings and sloping cathedral ceilings are becoming popular, and that means more heat for the same floor space in my house.

@HeatGeek1

Жыл бұрын

While the volume is relevant, the primary issue comes in at the "thermal envelope" - the point at which heat enters or leaves the home. The more airtight and well insulated the home is, the smaller the system is in general terms. There are many other factors, but the evaluation of the "thermal envelope" in all its features is critical.

@rtel123

Жыл бұрын

@@HeatGeek1 of course yours is also part of the calculation, but when the temp drops that one degree to trigger the furnace, heating 50% more air volume 1 degree will take 50% more btu.

@HeatGeek1

Жыл бұрын

@@rtel123 sorry, I don't understand what you're trying to express.

@TheCyberMantis

Жыл бұрын

Warm air rises. High cathedral ceilings require ceiling fans to push the warm air back down to where the humans are. What good is a warm ceiling if the floor is freezing cold.

@valeriegould1769

Жыл бұрын

YES! Cubic feet is a far better analysis choice. My mother's house has a huge cathedral ceiling (well over 10 ft in the living room AND both bedrooms. The square footage is 2079. It came with a 3 ton AC unit which is already a bit undersized. Add to the cathedral ceilings that it was in the Palm Springs area of California where temperatures really soared in late spring, summer, and early fall. The AC bills were huge as the AC ran constantly and it took forever to cool the house. When it broke, we upsized it to 5 ton over the objections of the HVAC tech. The house started cooling down much more quickly and our bills dropped drastically. Our air never turned cold and clammyl. We've had it for 20 years and are having to add freon yearly. When it stops working I plan to get heat pump system for it and make sure it is also a 5 ton system. Thank you for pointing out that cubic feet is a far better choice for many homes especially those with high or very high ceilings. And yes, we have ceiling fans in all of the bedrooms and the living rooms which all have the very high cathedral ceilings. Average summer temps are 112. The 5 ton handles it without any problem. The 3 ton could not.

outstanding

A schedule J calculation should be done on any house before choosing a unit. Our new house has 2500sf downstairs and only needed a 3 ton unit. Located in South Alabama, with 2x6 exterior walls with a complete spray foamed envelope. Wrap around porches on threes sides. House lined up on a true East / West axis. All windows E-336 glass. Upstairs has 2080sf, fully foamed and needed a 2 ton unit.

@fredjohnson2719

Жыл бұрын

Manual J or manual N but yes

@albertpitts3173

11 ай бұрын

That's the right way to do it.

We recently replaced our 30+ year old 2 ton AC unit with a 2 stage 3 ton AC for our two story 950 square foot house. When the old AC was working it's not enough to cool the upstairs so we went with 3 ton. Glad we did as it made a big difference. The house was built in 1989 but it had alot of insulation improvements over the years. It's not really about square footage but actual air volume in the home. Multiple stories also makes a difference. Wish we could afford a two zone AC system but considering it was already expensive as it is we went with 3 ton 2 stage to cover the entire house.

@valeriegould1769

10 ай бұрын

Don't forget cathedral ceilings count as another story.

@rupe53

10 ай бұрын

@@valeriegould1769 ... maybe not a whole second story, but you certainly need to add something for the extra cubic feet. Oh, and with an older home, you most likely don't have 12" of insulation against the roof. That's a killer right there.

@jbar_85

7 ай бұрын

Thankfully you got two stage. Had you not, you would be dealing with humidity issues especially if you live in a humid area.

Thank you for this. I live in a mobile home 43 miles north of Florida in southeast Georgia. IMO, mobile homes need 20%-33% more tonnage for cooling, maybe for heat, too. They are just not built as well, not insulated as well, & ducts are not sized properly, usually. Have a GREAT day, Neighbor!

@tylough

Жыл бұрын

They have more exterior surface area than a more square shaped house.

@GazeCema

8 ай бұрын

Zennihome. The new pre-fab homes are pretty good.

Thanks for this. I live in Austin, TX. Our 2 story house was built in 1992, has a 15 ft front entryway and dining room and then 9 ft ceilings on the first floor. The stairway is very open to the second floor but thankfully we have a small landing and then all bedrooms and bathroom doors are close to each other. We have a hard time keeping the downstairs cool. We have 2 units and use the downstairs during the day and then take the thermostat up when we go upstairs for bed and vice versa during the day and night. Our downstairs is almost 1600 sq ft while our upstairs is almost 2000 sq ft. The upstairs does OK but our downstairs can be a struggle especially when we have people over for a gathering. Would would be recommended for this type of scenario? High ceilings in Austin, TX? Thank you.

As other stated there are so many other factors here that are not mentioned, a manual load calc is needed as a starting point. I also would argue that anyone installing a new HVAC system should only consider a variable speed unit and slightly oversizing is a good idea knowing that the system will be able to more quickly bring the home to temperature and then run at 30-50% load to maintain the setpoint. An oversize unit will also be able to keep up with the weather extremes that seem to happen with climate change.

Excellent

Based off this video I think I need a 4 ton vs the current 3.5 ton. Central Florida home built in 2007, two-story, 2260 sqft.

depends on where you live!!!!!!!!! im here in phoenix try a 3 1/2 ton on a 2000 sq ft home here!!! your going to be pulling that out the first summer.....

Excellent video. a lot of useful information. I currently have a 100,000 btu gas furnace which I need to replace due to 3.5 ton compressor going bad along with 400sqt addition which bring the house to around 1800sqt with 10 big windows. What size btu furnace and compressor would you ruffly recommend for the size house. I think the unit is 28+ years old. Do i go with 115 or higher btu furnace n a 4 ton compressor or stay with the 100btu n the 3.5 ton compressor.

In Texas go one size higher. My ac unit barely breaks a sweat. And cut my ac bill in half.

@valeriegould1769

6 ай бұрын

Same in the desert in California. We upsized to a 5 ton from a 3 ton and our electric bills were almost half due to the ac not running constantly. We keep our ac at 75.

I have a DRH home with a 2.5 ton unit on a 2.083 square foot. The funny thing is all the house have a 2.5 ton even the smaller homes.

It’s a lot more factors that play a part. A manual j should be performed. Your area elevation average temp etc. your roof , windows , doors , foundation, insulation , roof color , finish on house, Which way your house face all play a part

In my thoughts, a climate like Arizona your dealing with a lot more sensible and no latent heat load. in that case I would size that system at 600 sqft per ton. In a case like Texas where you have very high latent heat and high sensible heat load I would size the system at 800 to 850 sqft/ ton. Yes you will have longer run times for the system, but you will bring the RH levels down significantly in the house. That makes for a more comfortable environment. Nobody likes a cold and damp feeling inside the house. It makes for longer run times for the system but that's why the manufactures invented higher SEER units. The Idea is to deal with the humidity first, or the latent heat load. then bring down the sensible heat load. Once you pull the humidity out of the space the temperature automatically feels colder. Here in central Canada/ the parries, we have a very low latent heat load, low humidity. We size residential A/C at 600 sqft/ton. When you move further down east to Ontario, Quebec and the Maritimes they have a very high latent and sensible heat load. In this case its in your best interest to under size these systems for longer run times to deal with the latent heat loads/ humidity first . The worst case scenario is when RH and Temperature intersect at 85 and 85, = instant black mold growing. Nobody wants the in their home. Keep the RH low and everything will be healthy in the house.

@nostradamus7648

2 ай бұрын

Great information. What size system do you suggest for a 2000 sq ft single story in San Antonio where average outdoor humidity is 60%. I'm replacing a 17 yo 3 ton 13 seer Trane heat pump.

I got a 4-5 ton switchable because I planned to do multiple additions. My house is only 2000 sq ft. Not sure if I wasted money too soon.

I have a 1000 square foot house with a 2 ton heat pump. It keeps up up to 90 degrees then above 90 degrees then runs almost all the time. 14 year old house post and beam construction. So 2 1/2 or 3 ton when it fails

All right let me ask you this I have garage about the size of a 2 car, it’s really more like a one and a half. I have a 1 1/2 ton unit all new install also insulation all been put in at the same time of the install. It won’t get below 78 runs all day long never shuts off even at night sounds undersize to me but it’s less than 800 ft.², does not have a garage door. I turned it into a workshop.

Hello like your videos, lots of information. I got one question so I have a manufactured home in sahuarita Arizona, very close to Tucson az. is a 1997 what size of ac compressor you recommend. The ac now is a 3 ton, is as old as the house it does all right is still cooling but is lacking a little so I’m in the hunt for a new system. If you can tell me what size of unit I would need, like you said in the video, older the house go bigger. So it’s 26 years old plus a mobile home insulation is very minimum on manufactured homes. Any info I’ll be very helpful. Keep up good work.

Great video! We had someone out looking at our home and they are trying to sell us a 4 ton (which is an upgrade) but we are in northern VA and our house is 3300 sqft. Why would they be trying to give us a 4 ton?

I live in El Paso. My house is 1500 sqft and was built in 2006. My AC is a 1.5 Ton unit. This is the original system and "overall" the house is cooled and heated without an problems. We do have hot and cold spots. This is a single stage unit. If the website is correct I would need a 2.5 ton system. My concern is that all the ducting will have to be redone to handle the larger Ton size and to balance the system with a 2.5 ton system.

@GUITARTIME2024

Жыл бұрын

Get an hvac quote(multiple). Also, you might get away with a 2 ton, but the 2 stage type. Also make sure you have 2 returns and don't use filters that are overly dense. I use MERV 11. You could also add a ceiling return if a certain bedroom is problematic.

how do you determine the ton that you need on homes built before the 60s?

Could you do on video on deciding factors of whether to go with one or two ac systems for 2 story homes?

@BrentS100

4 ай бұрын

Always two systems on a 2 story home for best results. Hvac contractor here.

@watchmanspector1642

15 күн бұрын

2 systems better - our state iecc codes say minimum 1 zone per story

So when you get a quote to replace the condenser does price include evaporator coil and heater and how can you tell. I don't need an evaporator coil or heater yet. AC is electric heater is gas. 2100 SF Austin Tx. Quote received for 4 ton Goodman Condensor (2023 SEER2), installed 10 year warranty

How about a log home with 1500 sqft downstairs with open living room and a separate unit for loft upstairs of 300 sqft? Built in 2002. In S.C.

Without Manual J calculation?

Please don’t do rule of thumb. Add a smart stat to add data for a working unit. It will record runtime and outside data. A year would be nice. Not all together wrong, but the variables can cause problems. Heat load is good. Still a fancy guess.

I am in round rock we have a 4 ton system and it is short cycling our house is 2300 sf

A buddy of mine was a mechanical engineer and pilot. He got his HVAC license and used it as a side gig and between career job. He would actually run heat calculations and was surprised most HVAC tech only used the “rule of thumb”. He also found that techs would not properly size the ductwork. This is why there are hot and cold spots in homes. My house is an ice box in my room and the kids are warm because the afternoon sun is shining on their rooms.

Interesting to look at this rule of thumb, as I bought an older house with a recently replaced HVAC system that was sold to the prior owner. SW Oklahoma, so in the northern part of Zone 1 on that chart. 1969 build, ~1200sq/ft, concrete slab foundation with wood frame construction. Mostly updated to double pane windows, though a couple older aluminum single pane ones. The system installed is a 3.5 ton system, which makes me wonder just why the system was chosen, as it's apparently a full ton oversized for the application. Profit margins? It doesn't run all that much of the time, often only a few hours a day during the middle of the summer.

@annaqsmith

3 күн бұрын

Yep definitely oversized.

How does a dehumidifier fit the picture? Also foam insulation. I have a 4,000 sq home but a 4-ton unit and it feels like it's always running. The A/C company says it's perfectly designed, but.... doesn't feel like it.

Should the finished basement square footage be considered if ALL the vents feeding that space are CLOSED when we run the A/C because it's naturally cool (almost cold) downstairs and doesn't need cooling? House is approximately 2900 sq ft total split evenly upstairs and down, 20 years old in southern Wisconsin.

Got a question for you. 10-12 years ago found a contractor I *really* like. Was very knowledgible on our situation. 2 story house.. Built in 1981. We're in the concrete jungle of DFW area and bought house in 1997. The HVAC was original from 81 with 2 units; 1 up and one down. I don't recall what tonnage each unit was, but it was not enough on top of 2 system barely functioning. The house was an investors quick flip, and basically it was indeed a pig with a lot of lipstick as we learned. After doing double pane windows and all doors replaced it didn't seem to work so hard. The insulation in each part of upper and lower floors is lacking at best. Rockwool average 3 inch. Masonry siding from bottom of 2nd floor up. Downstairs brick up to ceiling+ a little.. No insulation on attic walls nor any radiant barrier on roof. Upstairs is around 1400 Sq Ft and downstairs is around 1750 sq ft. Contractor suggested a 2.5 ton upstairs and wanted us to do a 3.5 ton downstairs, both single stage systems. For just a little more we went with a 16 SEER 4 ton 2 speed down stairs, which has been perfect match. Downstairs rarely kicks into high stage and can hardly even tell it's on. The upstairs 14 SEER 2.5 ton single stage does the job really well, but it does run quite a bit more during the warm to hot days. These units were installed in 2008 and have for the most part been trouble free. The 4 ton burnt up a compressor about 5 years ago, so he recommended we drop down to 3.5 ton single stage. I really didn't want to do that as we _love the quietness_ of the 2 stage system. So we opted for the 4 Ton 2 stage. Indoor humidity on the really hot days both up and down run in low 40% range during AC season. Over past few years, a new coil and outdoor unit goes thru CAPs ever couple of years.. Thus we are at a crossroads again, as to what to do. _Wondering why he seems insistent on dropping down to a 3.5 ton?_ Cant underdstand the push.. I know the #'s dont line up and a 3 ton would probably be the proper unit, but it does not come in a 2 stage compressor. IDEAS, SUGGESTIONS?

@valeriegould1769

6 ай бұрын

I'd get a second and third opinion. I'd also ask the contractor you like why he thinks downsizing would help. It does not seem logical to me. Upsizing does seem logical since normally things burn out when they are chronically overworked. Please let us know what happens. Oh, one other item. I'd google "Why do I have to keep replacing the coil and CAP on my ac". Googling has often found the answer for me quickly.

ASHRAE has calculations for sizing. Typically on 95% of the worst extreme days the unit should run continuously. So essentially the most extreme few days of a summer the AC will run continuously in afternoon.

@joshuaseaton7002

2 ай бұрын

No, the most extreme days, if you follow the Manual J, it will not keep up. The proper sizing will have it run continuously under it's design conditions. Extreme temperatures are not design conditions.

Two story homes present a different problem in regard to size also

@BrianNC81

Жыл бұрын

Two separate units is optimal for a two story home.

@bobboscarato1313

Жыл бұрын

@@BrianNC81 True. If you live there for a long time, is worth the extra cost!

@BrianNC81

Жыл бұрын

@@bobboscarato1313 I'm thankful our home came with separate units for downstairs and upstairs but it will increase costs when it comes time to replace them. The previous owner of the house had them replaced around the same time.

@BroadwayLTDProductions

9 ай бұрын

Yeah when I was a teen we had this big, 3,100 sq foot two story home WITH a basement! Balancing that house was a PITA!!!! But at least the equipment was sized properly (4 ton a/c with 80,000 BTU output gas furnace). The house was located in Indianapolis. Two systems would have been better though.

What if you have a finished basement. Should that be included in your living space.

If your A/C contractor is using square footage and not Manual J for sizing the system and is basing duct size off of cfm per ton and not Manual D.....RUN!

Is it better measuring in cubed feet

I can understand that heat load can be a factor for the difference of around 20%. I live in India and our general prescription is around 12000 BTU for 150 square feet This is for concrete buildings with moderate insulation. I still don't understand why the difference is up to three times. Can you please explain?

What is a heat load?

Great video! Thanks. When considering the size of the system I was hoping you would address the volume of a room, high vaulted ceilings plus 9 foot flat ceilings increase the volume we are cooling vs 8 foot ceilings throughout.

@SDGreg

Жыл бұрын

I was hoping the same thing. I have a 3800 square foot home with several areas of vaulted ceiling that currently has 2x3-ton units that doesn't seem to cool properly during hot days.

@HeatGeek1

Жыл бұрын

The extra foot or so of ceiling height is factored into a proper manual j load calculation but generally speaking it's not a huge difference in the heat load. Other things like window quality orientation and shading are far more significant than ceiling height, but in truth there are so many factors I couldn't even begin to list them here. I'm sorry but I don't recommend listening to this guy. He mentions doing " a quick heat load calculation before you purchase". Quick load calcs are sloppy load calcs. Good ones take time and diligence. This is more of a sales video than anything else.

@Mach141

Жыл бұрын

HVAC contractors dont do heat load calcs, they use this chart and call it a day. A proper one is very involved / time consuming and cuts into their profits. They are all about slapping in some overpriced equipment as quickly as possible and making several thousand profit per house.

@HeatGeek1

Жыл бұрын

@@Mach141 true/not true. I agree that many, even most don't do a serious manual J, but there are those that do. Clearly you haven't met me, or you wouldn't say that. I would also say, what kind of manual j are you looking for? A free one? A $300 one? A $2500 one? I only do a manual j after I have the job(with first payment) Everything else is moot to me. I won't trust someone else's work either. On pricing- people pay for what they want. Some people WANT financing, Mercedes vans, TV commercials, techs with white collared shirts with everything but the cufflinks(LOL) If that's what they want then that's what they pay for. If you don't want that, but rather honesty, technical competence, and a commitment to quality then you have to go looking for it. If you just assume that Mr White shirt will deliver those things you are likely screwing yourself.

@Mach141

Жыл бұрын

@@HeatGeek1 I'm not in the business. When I last replaced my system (2017) I was reading online about tons and sizing, and came across this "proper" method of sizing a home, this manual J. I read over it and was really surprised at what one requires, and quickly realized that most in the business aren't going to these lengths. As a retired Aircraft Maint. tech, we dont take shortcuts. Shortcuts can cost lives. So with that mindset, I figured a proper J manual should be done on every house, by every A/C contractor. Should it not? I'm assuming following the temp. zone chart is "good enough", and thats why it is the way it is. If you actually do one, good on you! I will hire you next time. Oh wait, you want to charge me $2,500 to do one? No thanks, the chart will have to be good enough

Odd result, IME. I’m in zone 4, 3700 total square feet and was manual J sized at, and have been living with for 25 years, a 2.5 ton system. The chart says 5 tons isn’t enough. It’s a pretty standard house - ceiling height, number of windows, number of doors, occupants, etc.

I have a 3 ton 16 seer for 2700 square feet in a fully spray foamed house. It’s a new home and the system ran for 6 hours and didn’t drop the temp from 78 to 76. The builder had a 6 inch duct unregulated fresh air coming in and he’s using the whole attic as a return air system. In my gut something feels off and that ac runs all the time. Any ideas? The charge is correct and it’s zoned with 5 thermostats

Just a question We have a 3 ton outside but in the attic it’s 3.5 or #46 not sure why they don’t match,any reason

As HeatGeek below notes - the thermal envelope is what matters . . .effectively the rate of heat transfer between the inside and the outside of the house. This can be calculated using the heat transfer coefficients for the various elements of the building - walls, doors, windows, foundation and roof - the areas of these elements individual elements (ft2) x the differential temperature (deg.F) and the Heat Transfer Coefficients (btu/ft2/deg.F). The volume inside the building x the specific heat capacity of air x the differential temperature allows you to calculate how much heating or cooling the fluid requires in addition to the heat losses from the building envelope and the speed at which you want it to cool also affects the size of the unit but also the heating/cooling system cycling time.

@JohnCap523

10 ай бұрын

Yes, or a Manual J which includes ALL relevant variables.

I have two units with a two story family room

We have 7 tons counting attached garage in a 1400 square foot home, upgrading to 8 this year.

@annaqsmith

3 күн бұрын

7 tpns for 1400sf?? That is way oversized! I hope this is a typo.

@martialman.4563

3 күн бұрын

@@annaqsmith Nope, keeps us cool.

Do you count the basement when you are counting square feet

There is no set btu/ft^2 at all. You have to model the house with manual J to get that value and maybe even manual D

Just bought a house who's owner was a HVAC tech, I took a peek in my attic and it looks like NASA did work in it. The main house 2300 sq ft has a Trane XR 16 - the unit is so big compared to what other houses in the neighborhood have. I don't know Jack so I'm guessing this guy went above what he needed. In zone 2/3 in Northern California. I have a single large upstairs bedroom (now entertainment room) which is on its on separate AC. Didnt know houses needed 2 AC units. Are 2 AC units normal?

What if my Air Handler is sized for 4 ton but the compressor is a 3.5 ton? I have 1800 Sqft house and I live in Orlando, Florida. I've been getting quotes for 3.5 ton and 4 ton Units. What size should I get?

My 5 ton can't keep up in south texas. Considering getting a bigger unit or supplemental smaller units. 108 degree days really do a number.

@atlasacrepair

3 ай бұрын

Man, we are right there with you, in the heart of Texas! Sucks that 5 ton is the biggest unit allowed for residential, we see MANY mini splits, that don't require any duct work. Hopefully it works out for you, but yeah our summers are no joke!

@atlasacrepair

3 ай бұрын

Any other Texas natives? 👀 We know all too well about that Texas heat 🔥

The results the Manual J calculation.

Hello, I want to replace my HVAC heat pump, it died. My house is 1456 sqft. and was built on a Slab in 1992. I live in Richmond, VA. Based on your chart, what's the best Ton? Thank you.

If I have 11’ ceilings with a 1800 square foot home can I go with 3.5 Ton, I live in Central Florida home built 2005.

My son has a 1640 Sq ft home in South Miss. Built in 1987 that has a 3 ton a/c unit that he just had serviced and the refrigerant is charged properly,duct work looks ok,insulation looks OK but his a/c unit runs all,the time in the summer,so you still think a 3 ton unit is Big enough? Doesn't seem so to me is what I'm afraid of and of course the a/c guy is pushing for him to buy a new system. I don't want him to have to buy window or portable a/c units but I'm trying to think of other options to a brand new unit as that is way too expensive

I've got a 1400 sq ft home with vaulted ceilings in half the house. The old system is 2.5 tons. Am I crazy to put in a 3.0 ton. The house was built in 96

better to have more rather than not having enough, especially when it comes to air conditioning and heating your home.

this assuming an average setpoit of 72-73? i know plenty of people that keep it 70 or even lower and may need to bump it up an extra half ton... also for houses with two units, two stories, and two air handling units splitting the sqft for each, and if the upstairs is on the edge may need to bump it up being on the second floor, unless good insulation in attic, newer build, or a good tree canopy to keep house cooler. i like to ask my friends does the unit run 100% for long periods at a time maybe in the summer but not 100+ good sign they are undersized as is.

Manual J , is the only way .

@bobboscarato1313

Жыл бұрын

Some other company published a manual with similar figures to Manual J.

You must do manual J! Leak tests! Gotta tear out the wall to see insulation and materials! That's why I never win a bid! 😂

I'm done with central air. Midea u shaped. 2 are cooling my whole house. They shut on and off. It is awesome.

Please help! I had a 4 Ton Split system put Three years ago. I still have the original contract before the job was started. The “Contractor” poorly installed the system. First off the unit is underneath the lowest part of my two stage deck and only has 8 inch’s of clearance. So it can’t be maintained as well the propellor fan is blowing the hot air up against the deck and recycling it back into the coils and so on. He blamed the realtor lol.” Yes I said her job was done when I bought the house and she is not qualified to give any advice about an HVAC system. He said that is where she said to put it”. So for the past three years I have been contacting him with calls and texts with a detailed log ,because he has done a scheduled no call no show literally 6 times. He was supposed to add three new ducks and another return. Well I’m so frustrated with him I just asked if he would just move the unit to where it should of been to begin with. He agreed, it only a minimum of 8 feet and a max of 10 feet of distance. He was confident that it should be fine because the lines would be less than a of 25 feet from the A Coil and 80k BTU System inside. Well he still has not shown up and will not answer a call or text message. What do I need to do to get him out of the way and get a real HVAC guy to come and correctly do the work? He is licensed and insured. Thanks in advance. 🫡

This is my recommendation. Only hire a HVAC contractor that does a manual J8 heat load calculation. There’s a lot of good videos on heat load calculation on KZread.

I had a new A/C system installed 10 years ago. It had a 10 year warranty which expired this February. I had the second start capacitor replaced 2 weeks ago. I live in Fort Worth. With this new reality of MONTHS of 100+ temps my AC system runs 13-15 hours a day and barely is able to get to 79 degrees. This is NOT financially practical. My home is 1765 square feet. How much should I have to bring the temps to a reasonable temp at less run time?

If my home is 1500sqft with 14ft feelings how would that be calculated on a 3/2 with the living room,dining,and kitchen open concept built in 2005

Ι hate when customers ask me this question. I always tell them I don't care what other contractors are doing. If you want the proper job you need a heat load calculation (which I don't know how to do) and the rest I can take care of. Bye for now.

HVAC contractors will invariably oversize an A/C system. There's two reasons why. 1) They earn more on the sale of a larger system, and 2) they do not want to run the risk of a customer complaining it can't cool down their house fast enough.

@rodgraff1782

Жыл бұрын

Systems that are two big will short cycle and not dehumidify properly. Excessive starts and stops will kill a system prematurely. The sensible heat ratio, for various areas has to figure into the equation. This has to do with how much humidity the system has to deal with.

@tonyedwards9972

Жыл бұрын

Thanks for saying " I don't know what I'm talking about, but heard it somewhere "

@MsAjax409

Жыл бұрын

@@tonyedwards9972 I do know what I'm talking about. I've installed boilers, heat pumps, conventional A/C systems, indirect and tankless water heaters, solar systems... Try being less condescending.

@tonyedwards9972

Жыл бұрын

@@MsAjax409 the main reason people oversize or undersized is lack of knowledge...no need for your resume, I don't hire women

@MsAjax409

Жыл бұрын

@@tonyedwards9972 You're saying that there are HVAC contractors that lack the knowledge needed to do their trade?

So I am ignorant with HVAC and my heat stopped working this morning before work but I have propane which heats my water and stove and they work but I assume my ac unit is what blows my heat. Today I noticed the fan isn't spinning but it is below freezing today so I am here to ask if heat can be blown through an airtemp ac unit. I am in NC by the way.

@atlasacrepair

3 ай бұрын

Hello, not sure if you saw my previous reply to your other comment, so I wanted to post it here so you can try to get that taken care of as quickly as possible! : Hello, all central AC systems should be able to both heat and cool your home, but if the indoor unit is not turning on, there could be a number of reasons as to why, but I suggest you start with the breaker. A lot of times in this situation, your breaker has tripped so I recommend checking that out, sometimes it's as easy as switching it back on! Hope this helps, stay warm!

Manual J

@Balticblue93

Жыл бұрын

Manual J, T and S are very important but J is the best start. Totally agree.

@The1JBanks

Жыл бұрын

Manual J 💪 do a proper load calc. No rule of thumb. Houses are being built tighter and tighter now and more insulation.

@Holop88

Жыл бұрын

DIY'ers typically dont care about RH and calculations. They just want heat or cool. I live in PNW and biggest issue I run into is ducting is incorrect and not so much units over or under sized.