The new regulations, which went into effect in January 2007, raised the minimum efficiency required for new air conditioning equipment, specifically from 10 SEER to 13 SEER. (The efficiency of central air systems is regulated by the U.S. Department of Energy. Systems are tested and assigned a Seasonal Energy Efficiency Ratio.).

Manufacturers are no longer making 10-SEER systems. While the regulation is relatively new, we've recommended 13-SEER equipment and higher for years.