About half of all energy used by households goes to heating and cooling the home. This gives energy-conscious builders a real incentive to find efficient HVAC equipment. The task should get simpler now that the Environmental Protection Agency (EPA) has extended its four-year-old Energy Star program to central air conditioners and heat pumps.

Energy Star is a market-based effort in which the EPA encourages manufacturers to make efficient, nonpolluting products. Products that meet specific target performance levels--generally in the top 20 percent of energy efficiency--will carry the Energy Star logo. For example, air source heat pumps need a Seasonal Energy Efficiency Ratio (SEER) of at least 12 to qualify.

The program aims to achieve major upgrades in 50 percent of all homes by 2010. If the program meets these goals, says EPA, it could save consumers over $350 million per year in heating and cooling bills by the year 2000.

The new equipment will cost $500 to $1,000 more than standard HVAC equipment, with paybacks of 4 to 10 years. EPA is organizing banks that will make loans for the extra cost. For a list of Energy Star certified equipment call 202-775-6650.