Choosing a new high-efficiency can save money and electricity. The required cooling capacity depends on the size of the room being cooled. The higher the EER rating, the more efficient the air conditioner. Look for units with an EER of 10.0 or above.
Proper sizing is very important for efficient air conditioning.
A bigger unit is not necessarily better because a unit that is too large will not cool an area uniformly. A small unit running for an extended period operates more efficiently and is more effective at dehumidifying than a large unit that cycles on and off too frequently. Based on size alone, an air conditioner generally needs 20 Btu for each square foot of living space. Other important factors to consider when selecting an air conditioner are room height, local climate, shading, window size, etc. Verify that your home's electrical system can meet the unit's power requirements.