Two facts should be kept in mind when selecting an air conditioning.

(1) The capacity (cooling power) of the air conditioner should be suitable for the room. The size of a room and the number of people using it help determine the capacity of the air conditioner needed.

(2) The electric power requirements for the air conditioner must match the electric system available for it.  Different air conditioners use various amounts of electricity to remove the same amount of heat. Engineers use a number, called the Energy Efficiency Ratio (EER), to measure how economically an air conditioner uses electricity. Most air conditioners have an EER of from 8 to 9. The higher the EER of a unit, the less electricity it uses--and the less it costs to operate.