After searching through a lot of websites how many BTU air conditioner per square foot I came up with my own article which is smaller and tells you straight from the beginning the answer.
Without any further introduction, the answer is around 20 BTU. In average you need 20 BTU for cooling a square foot of an average room. The bigger the surface, the lesser the BTU’s needed.
How Many BTU Air Conditioner Per Square Foot
The amount of BTU / hour needed to cool down a room depend on some factors like the position of the room related to the sun, how many people are in the room, how many windows and how cool you want it.
In the following chart you can check how many BTU’s you need for a known surface of a room or even a small house. You can see also how many BTU air conditioner per square foot you need.
| Room Size (square feet) | BTU’s Needed | BTU/square foot |
| 150 | 5000 | 33.30 |
| 250 | 6000 | 24.00 |
| 300 | 7000 | 23.30 |
| 350 | 8000 | 22.85 |
| 400 | 9000 | 22.50 |
| 450 | 10000 | 22.20 |
| 550 | 12000 | 21.81 |
| 700 | 14000 | 20.00 |
| 1000 | 18000 | 18.00 |
| 1200 | 21000 | 17.50 |
| 1400 | 23000 | 16.42 |
| 1600 | 25000 | 15.62 |
| 1900 | 28000 | 14.73 |
| 2700 | 36000 | 13.33 |
As you can see, the bigger the surface you need to service with the air conditioner, the lesser BTU’s per square foot you need. This is because the bigger is the area which needs to be cooled down, the lesser is the proportion of walls, windows and other construction elements which permit heat to sneak in.
First of all you will need to calculate the surface of your room or house. If you don’t know how, please read my article on how to calculate the area of a room.
Like you I was searching some time ago for how many BTU air conditioner per square foot. I needed to cool down my office and I bought the a 12,000 BTU air conditioner, ending up with about 19,5 BTU per square foot.
