How Do You Calculate the BTU of an Air Conditioner?

BTU is an abbreviation for British Thermal Unit, which is the international measure of energy. An air conditioner's BTU must be matched to the size of the room for adequate cooling. BTU tables estimate different energy requirements.

According to the BTU Calculator at Good Housekeeping, a sunny room with excellent insulation and an area of 700 to 1,000 square feet requires 19,800 BTUs to cool. Therefore, if a person is planning to buy an air conditioner for cooling such a room, its energy capacity should be at least 20,000 BTUs.