The Air Conditioner BTUs Needed for 250 Square Feet

Cooling

• Air conditioners remove the humidity and heat from a room to make it comfortable. As the hot air passes over the refrigerant coils, the heated air is cooled and sent back into the room. During the cooling process the humidity is removed from the air, which reduces the heat index in the room.

Wrong Size

• If the air conditioner has more BTUs than what is needed for the square footage, the unit will cool the room quickly, but it won't remove the humidity. The result will be a unit that shuts off and on, while leaving the air feeling damp. A unit that is too small will run all the time, but not cool the room as it should. The room will feel slightly muggy because the small unit doesn't completely remove the humidity and heat to make the room comfortable.

Reducing BTUs

• When choosing a window unit for a 250-square-foot room, you can reduce the BTUs needed to cool the room by 10 percent if the room is heavily shaded and does not receive a great deal of direct sunlight. For instance, a room with 250 square feet that receives no direct sunlight can use an air conditioner with 6,300 BTUs.

Increasing BTUs

• A 250-square-foot room that gets direct sunlight will need a slightly larger window unit. Increase the BTUs by 10 percent if the room will receive any amount of afternoon sunlight. If the room will have more than two people in it while the unit is running, add 600 BTUs for each additional person. For a 250-square-foot room with three people in the room regularly, you would need a unit with 7,600 BTUs.

Kitchen Use

• In a 250-square-foot kitchen, you need to add an additional 4,000 BTUs. Kitchens have heat generating from the refrigerator and other appliances. To keep the room cool and remove the humidity and added humidity from cooking or doing dishes, you need a 11,000 BTU air conditioner.