SEER / SEER2

SEER stands for Seasonal Energy Efficiency Ratio, the score that tells you how much cooling an air conditioner or heat pump delivers for the electricity it uses across a cooling season. It is the cooling work done divided by the energy consumed, so a higher SEER unit gives you the same cool air for fewer watts and a smaller summer bill.

On January 1, 2023, the U.S. Department of Energy switched the test procedure and the label to SEER2, which measures the same thing under more realistic conditions (higher static pressure, closer to a real duct system). Because the test is tougher, a unit's SEER2 number is a little lower than its old SEER number for the same hardware. A model rated 15 SEER is about 14.3 SEER2. The federal minimum for new split-system air conditioners in the South, which includes Arizona, is 14.3 SEER2.

For example, in the Phoenix metro, where the air conditioner runs from spring into fall, the gap between a 14.3 SEER2 builder-grade unit and an 18 SEER2 unit shows up on every summer power bill. The higher-efficiency system costs more up front and pays it back over years of long cooling seasons. Heat pumps carry a matching heating score, HSPF2, that replaced HSPF on the same date.

SEER2 rates seasonal performance, while EER2 rates efficiency at one hot design point, useful in a desert climate where peak load matters. SEER2 is not a quality grade by itself. Right-sizing the unit, sealing the ducts, and the insulation R-value all decide whether you get the efficiency you paid for. We size and spec HVAC to the home and the Arizona load, not to a sticker number alone.