New federal efficiency standards for residential air conditioners and heat pumps went into effect January 23, 2006. The national minimum for cooling efficiency for air conditioners and heat pumps manufactured after the 23rd will be 30 percent higher than the current standard.

The U.S. Department of Energy (DOE) standards only apply to air conditioners and heat pumps manufactured in the United States after January 23, so this change won't have an immediate effect on homeowners. The standards do not apply to existing equipment, and there's no problem installing a unit manufactured before January 23. In the long run, though, the DOE estimates that the new standards will save 4.2 quads (quadrillion British Thermal Units) of energy and save consumers more than $1 billion in energy costs over the next 25 years.

The new standard for whole-house air conditioners raises the energy-efficiency standard from 10 to 13 SEER (Seasonal Energy Efficiency Ratio). The new air-source heat pump standard raises the cooling efficiency from 10 to 13 SEER and the heating efficiency from 6.8 to 7.7 HSPF (Heating Seasonal Performance Factor). That's a 30 percent improvement for cooling and a 13 percent improvement for heating. The SEER is a measure of the seasonal cooling efficiency of whole-house air conditioners and heat pumps. The HSPF is a measure of the unit's seasonal heating efficiency, including both the compressor and the electric-heating elements. These measures are similar to the Environmental Protection Agency's gas mileage estimates — they are based on certain test conditions and assumptions.

The old minimum efficiency standards for air conditioners were set in 1993. Before 1979, the SEERs of central air conditioners ranged from 4.5 to 8.0. Replacing an older unit with a SEER of 6 with a new 12-SEER unit can cut your air conditioning costs in half. This may also be affected by your duct system's performance.

The new standards shouldn't affect the maintenance of your existing system. Whole-house air conditioners and heat pumps typically last more than 15 years, and manufacturers usually plan to support existing equipment that long.

Remember, the new standards are minimum standards. More efficient models are available, and the more efficient your heating and cooling equipment is, the more you'll save in the long run.

For more information, see the DOE's Web information on the new standards.

Why Standards?

The U.S. Department of Energy sets minimum efficiency standards for appliances such as refrigerators, motors, clothes washers, water heaters and heating and air conditioning equipment. The nonprofit American Council for an Energy-Efficient Economy (ACEEE) says that energy-efficiency standards are one of the most effective ways to reduce overall energy use.

According to ACEEE, minimum efficiency standards help overcome market forces that might restrict the use of more efficient products. These include:

Decision makers such as landlords and builders who purchase appliances but don't pay the operating costs; and

The fact that many appliances such as refrigerators and water heaters must be purchased on an emergency basis, leaving little time for consumers to compare features.

Studies by ACEEE and DOE estimate that the DOE minimum-efficiency standards reduced U.S. electricity use by about 88 billion kWh and reduced U.S. total energy use by about 1,200 trillion BTUs in 2002. Between 1990 and 2000, minimum efficiency standards have reduced energy bills by about $50 billion. While equipment prices have risen slightly due to standards, estimates by the Lawrence Berkeley National Laboratory and ACEEE indicate that the benefits are more than three times the costs.