SEER2
The updated 2023 efficiency rating for AC and heat pumps — higher SEER2 means lower cooling bills.
SEER2 (Seasonal Energy Efficiency Ratio 2) measures how much cooling an air conditioner delivers per unit of electricity across a whole season — the higher the number, the cheaper it is to run. The '2' marks a 2023 update to a tougher M1 test that raised the external static pressure from 0.1 to 0.5 inches of water to better mimic real ductwork, so a SEER2 figure runs slightly lower than the old SEER number for the same equipment. Minimum SEER2 is regional: roughly 13.4 in northern states and 14.3 across the South and Southwest. When you [replace a central AC](/guides/central-ac-replacement-cost), paying for a higher SEER2 tier lowers your bills and improves humidity control — a trade-off that pays off fastest in hot, long-cooling-season climates.