If you buy a central air conditioner with the Energy Star label, your equipment will be at least 20% more efficient than standard equipment.

Fossil fuels burned to cool and heat your home contribute to air pollution problems such as smog, acid rain, and global warming. The Energy Star Label means an appliance meets the Environmental Protection Agency's (EPA) standards by using less energy and thereby reducing pollution. To display the Energy Star label, appliances, heaters, air conditioners, and heat pumps must meet strict specifications, which make them markedly more efficient that appliances meeting minimum government standards. For example, central air conditioners and heat pumps must have at least a 12 SEER rating to display the Energy Star label.

Seasonal Energy Efficiency Ratio:

Is the efficiency rating for air conditioning units. Higher SEER rating means more energy is used more efficiently. SEER is the ratio of the amount of BTUs used for cooling in normal annual use to the total amount of electrical power (measured in watts) over the same period. (Annual Cooling in BTU's/Total Watt Hours = SEER).