"Purchasing an energy-efficient system allows a homeowner to save on energy costs and protect the environment. Even if your air conditioner is only ten years old, you may save significantly on your cooling energy costs by replacing it with a newer, more efficient model. Products with EPA's Energy Star® label can save homeowners 10% to 40% on their heating and cooling bills every year. Both R-22 and R-410A systems may have the Energy Star® label. The U.S. Department of Energy specifies the minimum efficiency of air conditioners sold in the United States. For central air conditioners and air-to-air heat pumps, efficiency is measured by the seasonal energy efficiency ratio (SEER). The higher the ratio, the more efficient the equipment, and equipment that displays the Energy Star® label must have a minimum seasonal energy efficiency ratio that is significantly higher than that required by law. You should consider energy efficiency, along with performance, reliability, and cost, in making your decision."