Window air conditioners are an ideal way for apartment residents and economical homeowners to cool off. But even though you don't have the money or room for central air conditioning, you will still want to get the coolest air out of your window AC unit.
A properly sized air conditioner will cool the entire room you are going to install it in, while not wasting electricity and money in the process.
If you purchase an air conditioner that is too small, the unit will be overworked trying to pump out more cool air than is possible and will eventually burn itself out. On the other hand, purchasing an air conditioner that is too large will cool off the room too quickly and the humidity will hang in the air, leaving you clammy and chilly.
You can determine the proper air conditioner size for a room by measuring the square feet of the room you wish to install it in - multiply the length by the width - to give you the room's square footage.
For example, a 12' by 24' room has 288 square feet. The following chart shows that 7,000 BTUs are recommended for a 288 square-foot room.
100-150 sq. ft.