New air conditioners are more energy-efficient than ever before. The best new air conditioners have improved coils, more efficient motors, variable-speed fans, and dual compressors. Air conditioners bearing the ENERGY STAR® seal are the most efficient of all, and use 10-20% less electricity than a standard new central air conditioner, and about 30-50% less electricity than an older central air conditioner.

All air conditioners are rated by the amount of heat they remove for each kilowatt-hour of electricity they use. Central air-conditioning units are rated by a Seasonal Energy Efficiency Ratio (SEER) and Energy Efficiency Ratio (EER). Room air conditioners are rated only by their EER. All air conditioners must display their energy ratings on yellow Energy Guide Labels.

The higher the SEER or EER rating, the more efficient the air conditioner and the lower its annual operating cost. An ENERGY STAR® seal requires SEER ratings of at least 13 for split system central air conditioners and SEER ratings of 12 or higher for packaged central air conditioners. Portable room air conditioners must have an EER of around 11 to qualify for the ENERGY STAR® seal.

If you install a new central air conditioner, be sure to work with a contractor who is willing to perform a quality installation. Recent studies show that more than half of central air conditioners don’t perform up to their potential because of one of the following installation problems:

•Air conditioner is oversized

•Ducts are leaky

•Airflow is restricted

•Refrigerant charge is incorrect