Cooling Capacity Calculator: How to Find the Right BTU for You

Not sure which portable, window or central air conditioner is right for your home or specific needs? We are here to help.

You’ll find below a pretty handy chart that will help you pinpoint the right model. You’ll notice that room size and heat load are the two variables within this chart. Step one is simply figure out the room size in square feet of the room you would like to keep cool. Next, figure out the amount of heat or "heat load" that the room receives. For example, if the room has a lot of windows or is next to a kitchen, that room would probably have a high heat load.

Based on those two parameters, you should be able to figure out what kind of BTU range works for you. For reference, BTU is simply a designation of cooling power – the higher the BTU the more powerful the cooling. Simply click on one of the four "BTU areas" and it will lead you to a page with portable air conditioner models that will suit your room size and heat load needs.

How to Calculate How Many BTU’s You Need

Use the dropdowns below to help you estimate what size air conditioner is best for your space. The cooling power of different types of air conditioners is based on BTU’s. We’ve rated and measured our units against a number of different room and/or home conditions that can effect the cooling power required.

Use the drop-down menu below to calculate the total BTU cooling power that you will need to efficiently cool down your specific needs.

Cooling Capacity Calculator

BTU Chart Based on Room Size

Don’t want to use the BTU calculator above? No worries. Here’s a reference chart that will give you a pretty good idea of how many BTU’s you will need, based on the total size of your room.

BTU Chart Based on Room Size

About Our Team

Kara Zorn is a wife and working mom who loves life hacks that help her schedule allow for as much quality family time as possible. She enjoys cooking with locally sourced food and produce and recently took up brewing Kombucha.

Comments

1. Ralphie says May 12, 2015 at 7:45 pm

Thank you. This information was actually pretty insightful. I live alone in a somewhat big house and there are many times I simply want to cool one or two rooms, especially my bedroom. And it doesn’t make sense to cool the entire house, just so I can sleep comfortably. I hate throwing money at the power company for rooms I’m not using. RS

Have slider windows what a/c unit will work for me window opening is 58 1/2 × 21 600 Sq ft sun room.

• BR says July 5, 2023 at 2:44 am

Only portable are do able for both types of windows
Thank you very much. it helped me.

• Astrid says May 19, 2023 at 7:30 pm

I have 2 5000 BTU UNITS working now. Can they hold this summer, to give me time for the building of another room?
I really appreciate your response. Thank you.
Astrid

I recently purchased a 14,000 BTU but discovered that it would turn off each time my refrigerator turned on, so I had to return it. Would lower BTU’s work or does it have to do with the amps? Please advise, and thanks!

• Jerry says July 19, 2016 at 3:57 pm

Having a smaller btu ac probably would help if it is still large enough to cool your space. The circuit which you have both of them plugged into is likely too small to handle the load of both at the same time. There may be a switch that shuts off the ac if the current draw is too large. You might be able to solve this by just plugging one of those appliances into a different circuit or just leaving the ac off until the fridge stops running.

plug into another outlet source your blowing the fuse on the plug from ac unit
Try using bigger fuse

• Dave says March 9, 2023 at 6:11 am

ABSOLUTELY NOT. Breakers are sized to protect the wire and you can’t indiscriminately go to a higher amperage breaker

sounds like your electrical supply for both appliances are connected together. Use a dedicated circuit for your a/c.
You can do this by having an electrician install another circuit breaker at the panel that controls the a/c unit.

All portable air conditioners that I have researched use sq.ft. as a condition for BTU requirement. I plan to use the unit to augment the central air in my bedroom which has a high cathedral ceiling. Wouldn’t volume be a better criteria than area? My son, an architect, recommended adding 50% to the sq.ft.

• Benny says August 18, 2019 at 10:27 pm

I had the same dilemma and went with an a/c 1/2 ton larger than recommended; the unit was cycling quickly and was not removing humidity. We reasoned that as hot air rises and the thermostat is about 4′ off the floor the cathedral ceiling was not an issue. We determined we had a gradient of temperatures at different heights but was pretty even from around 10 ft to the floor.

I have a 14×17 foot sunroom 6 sliding glass doors and too large triangle windows up high, no insulation it is on the south side of house will this unit cool my room?

Hi Gang, I am looking for a window airconditioner for my apartment. There are 2 bedrooms a kitchen and a combination living and dining room. Total squre footage is approximately 780. I’d like to buy one that would provide airconditioning for the whole appartment. Does anyone know how large a unit I would need? or if it’s possible to A/C the whole apartment? Thanks a bunch. Jim

• gorge De la Paz says August 17, 2018 at 9:09 pm

your best choice is 6,000 b t u for each bedroom and a 12,000 b t u for the living room kitchen and dining room
separate a/c can be controlled in each room and then turn off the room you are not using less wasted and less tear and wear on the a/ c and then they may last 2 to 4 years longer by not using one a/c 18 to 24 hours a day

always recommend not one but 3 a/c 6,000 b t u for each bedroom and a 12,000 b t u in the living room , less tear and wear on just one a/ c ,one a/c would have to run 20 to 24 hours a days and will for sure shorten the life span of this one unit down by 2 to 4 years , 3 a/c may last as much as 2 to 4 years longer

• Carlos Navar says July 3, 2023 at 8:54 pm

I just built an ad on room to my house square feet is 780 what kind of unit do I need to the walls are 10 feet tall with a metal roof

Hello there, can any one help me.I have an airconditioner, but dont know what the BTU is on it.
It does not show anywhere,but it says 430m/h with a little 3 on the 430M.I dont know it it is sq.ft or sq.meters.Just want to know the BTU. It also says 3266W. The name is PROKLIMA M110
Hope any one can help me with the amount of BTU
Thanks

how can i convert btu to horse power

• SteveB says September 4, 2017 at 4:03 am

From what I can find but math is not my thing. The horsepower hours unit number 0.00039 hp h converts to 1 BTU. somehow equates to: 1 horsepower hp = 2,544.43 btu per hour btu/h. Calculators work better for me!

• rod clemente says October 18, 2017 at 7:10 am

it’s very easy to access,you don’t need to read many books,just click it and it will appear

How much BTU cooling is required for Dell 530 server having power consumption of 750 W .
As per my calculation with least 60% efficiency it will be 2577 BTU/hr .
Is it ok?

• Harin says September 29, 2018 at 7:31 am

Use Dell power calculator
model number RXN50KEV1B is how many btu

I have a 9 by 15 room which comes to 135 square feet would a 15000 BTU air conditioner be too much? I would have rather have too much than too little

• Gerald Lucidos says January 30, 2018 at 2:31 am

it will depends how many people entering on that room and consider also you isolation or sealed is that room and if it shaded or sunny area. i think 15000 BTU is too big remember that when your machine was too big it will cause high electricity bills and due of switch off and on of your machine.

1. 1 feet = 0.3048 meter
2. 1 meter = 3.28 feet
3. 1 square foot = 0.092 square meter
4. 1 square meter = 10.76 square feet
5. 1 watt = 3.412 BTU per hour
6. 1 horsepower = 745.69 watts
7. 1 Btu/hr = 0.293 watts
8. 1 ton = 11956.14 BTU per hour
9. 1 horsepower = 2544.4342 BTU/hour
10. 450-550 square feet = 12000 BTU per hour
11. 700-1000 square feet = 18000 BTU per hour
12. 1400-1500 square feet = 24000 Btu per hour
13. – 10% if the area is shaded
14. + 10% if the area is sunny
and for your EER or energy efficiency ratio
EER= btu/hr devided by watts I hope it could help.

• Fahim says September 19, 2019 at 8:22 pm

It’s going to effect how many people in the room ?

I have a Bedroom Size 12×11 can you help me and obtain the proper size Air Conditioner and it is I Dominican Republic where temperature is 90 deg ,this bedroom is is face to the west facing the afternoon Sun

What would you recommend as a replacement roof AC on a 1978 Spartan park model. 8×33, 2 people, skirted in full AZ. sun.

Sweet. I was just looking at your window units and scratching my head to what siZe I needed. This is exactly what I needed.

My fruits cold room is 11.6m W x 5.8m D x 3.5m H. Can you help to calculate how many HP or BTU shall it needed?

Thanks a lot …
It helped me a lot to understand BTU range..
And the BTU calculator was a bonus. Thanks
Love from India

How many but for a 3 bedroom ranch to cool down the whole house?

• Gorge De La paz says August 17, 2018 at 9:00 pm

a 3 bedroom unit or ranch with living room kitchen and bathroom you are talking about 2 choices a 1800 b t u or the second choice 12,000 220 volts outlet in the living room and 6000,
b t u in each bedroom i would do the 3 in each bedroom and one in the living room you will save in the long run if you are not in the kitchen and living room at night turn that one off and save a lot ,but only one for the whole house would pretty much have to run 20 to 24 hour a day more expensive and in about 6 to 8 years would have to replace the unit to much work for one ac, now a good 2 or 2 1/ 2 ton central may last you 10 to 14 years
with good semi annual maintanence if you can afford the $ 5,800 with the duck work and labor

How many BTU do I need to cool down 3 bedroom ranch?

I can’t currently afford central air or even a used portable unit over 14000 BTU’s but what I’m wondering is if a 13000 BTU unit will at least take the edge off in my 570 sq ft living room/kitchen combo with high (12ft) ceilings in a very sunny location. Maybe it won’t ever be cold or cool but if it could at least be more comfortable than 85 degrees, I’d be happy.

I live in an apartment with my husband. Two bedrooms and bathrooms upstairs, kitchen and living room downstairs. I just want one ac unit to cool off the entire apartment. How many btu’s would I need?

• gorge De la Paz says August 17, 2018 at 8:40 pm

i have a small apt 21 x 19 or about 400 sq. feet my a/c
is 10,000 and it’s a wall a/ c and it is more than enough you will not be able to do it with just one “cause the a/c downstairs will not travel up or the one upstairs will not travel completely down to many curbs and wall, you would be best with 2
8,000 b t u

A parameter to add to the BTU-age calculator would be to include “Are you up north or down south?”. If you use it as-is up north, 3 days of 95F will tax it, but is temporary. But 3 MONTHS of 95F is a different matter – and will kill the poor A/C unit in short order. For down south, you’d want to take the result and multiply by a good 1.5 so the compressor isn’t going 24/7 during the 3 month hot spell. And if the units to choose from are not exact, go with the bigger one for the reason above.

What is the capacity of Panasonic CS/CU-A 9 PKH? Is this good enough for a room size 12ft by 10ft? The manual does not give capacity of the air conditioner.

i have medium size apt. 19 x 21 = 399 sq. feet or better say total 400 , one bedroom , bath ,8 feet long kitchen, small living room and small dining room , and i have a 10, 000 b t u in the wall a/c and it is more than enough , at night i turn up my a/c to 70 degrees and the speed fan to # 2 , this is after being on 60 % of the day at 64 degrees, so you are going to need 12,000 b t u for sure, with that extra bedroom

Yes! The comment above for North and South is very correct. I live in Louisiana and I’m replacing a 18000 BTU in my 750 sq ft livingeoom/kitchen area in my mobile home with a 24000 BTU. Last summer was horrible , the lady who owned it before didn’t buy a big enough unit. After sweating through months of 95 degree days I had enough. We had a metal roof installed that helped, but the whole home is full sun. Yes min. requirements for a week or two up north will get you by, but months of 95+ heat with minimal BTU will just make you mad and kill your unit. I would go up a size atleast depending on your area. Another example my daughter had a 5000 BTU Ac in her 178 sq foot room. It only just cooled it enough to sleep at night. In the daytime it was useless. I often wondered how she could even sleep half her teenage day in there. We also upgraded it this summer. We moved the 18000 BTU to our room which is about 300sq ft
I think it will be too big, but I shall see. We now have AC’s larger than recommended in each room but the bathrooms. Hopefully come 3 p.m. any day in July we will be cool enough to breath.

This was SO helpful, we had 3 HVAC dealers come in and each one quoted on a different size unit.
We had compared SEER, EER and HSPF but needed to confirm what size we actually needed for our room size, this chart made the decision very easy! Thank you.

Thanks for the information. I have. 12×11 bedroom in which I have a. 14000 btu and for the rest of the home which total sq. ft is 840 I have a 18000 btu. They both have energy efficiency settings and I can run the larger one to cool whole home only if I cooking or using the oven I might have to turn both on during the day. But at night use the one in bedroom.

Thanks realy useful information
Ismail Pakistan
How many Btu’s needed to cool 2050sqft. home?

• CompactAppliance.com says July 17, 2023 at 7:32 pm

Hi Amber,
Thanks for the question! You’ll want between 30,000 to 34,000 BTU to cover an area that large.
Hope this helps!

I have a 2400 sq foot house how big q system do i need

• CompactAppliance.com says July 17, 2023 at 7:30 pm

You’re going to want something capable of upwards of 34,000 BTU to cover an area that large.

Hi. Im looking to buy portable floor ac. I live in 800 sq ft home. The kitchen livingroom combined. I wanna see how big of ac i should get btu

• CompactAppliance.com says July 17, 2023 at 8:31 pm

Hi Kim! For a home of that size, you’re going to want to get an air conditioner that produces around 14,000 BTU. If you’re only concerned about the living room and kitchen, you shouldn’t need more than 12,000 BTU.