Choose the Right Size Air Conditioner for Your Room (2)

The result of these calculations will give you the approximate number of BTU's your new air conditioner will need to have.

Does the formula sound complicated? It's really not. All the numbers in the calculation are necessary. That way, the volume of your room, the exposure of the outside elements, and the rating of the insulation are all taken into consideration.

Let me give you the example of my living room. I purchased a window air conditioner for this room, and the formula gave me the perfect size. My living room is 20 feet long, 18 feet wide, and 8 feet high. I multiplied 20 by 18 by 8 which equals 2,880. The wall that is most exposed to the outside elements is the south side. The corresponding number for south is 18. So I multiplied the 2,880 by 18. The result is 51,840. Next, I determined that the insulation level of my home is good. A "good" level is a number 5. Finally, I divided 51,840 by 5. The resulting number is 10,368. After I rounded it off, this told me that I needed to purchase a 10,000 BTU air conditioner. They come in sizes from 5,000 BTU's all the way up to 24,000 BTU's.