Two numbers dominate a heat pump spec sheet: SEER2 for cooling efficiency and HSPF2 for heating efficiency. Higher is better on both, but the meaningful question is how a model compares to the federal minimum and the ENERGY STAR bar.
The federal minimums
Every new heat pump has to clear a floor. Carrier notes that as of 2023, the Department of Energy requires a minimum of 14.3 SEER2 for residential air-source split systems, and that the DOE established 7.5 HSPF2 as the minimum standard for residential split-system heat pumps. Those two numbers are the baseline. A unit at 14.3 SEER2 and 7.5 HSPF2 is legal and new, but it is the least efficient equipment currently sold, not a high-performance choice.
What counts as high efficiency
Above the floor, there is a wide range. Carrier states that models rated 17 SEER2 and above are considered high efficiency, with some top-tier models reaching up to 22 SEER2. On the heating side, Carrier notes above 9 HSPF2 is high-efficiency, with top performers reaching 10.5 HSPF2. So when you compare quotes, a 17-plus SEER2 and 9-plus HSPF2 unit is genuinely in the efficient tier, while anything hovering near 14.3 and 7.5 is entry level.
The ENERGY STAR bar
ENERGY STAR sets a higher, tested threshold than the federal minimum. For standard split-system heat pumps, ENERGY STAR requires at least 7.8 HSPF2, at least 15.2 SEER2, and at least 11.0 EER2. That EER2 figure is a third rating, measuring cooling efficiency at a fixed high outdoor temperature rather than across a season. Choosing an ENERGY STAR model guarantees you are above the federal floor on both seasonal ratings, which is a simple way to avoid the least efficient equipment.
The cold-climate thresholds go further
For cold regions, ENERGY STAR adds a Cold Climate tier with tougher rules. A qualifying model must post a COP at 5F of at least 1.75 and retain heating capacity at 5F of at least 70% of its capacity at 47F. Cold-climate ducted split systems must reach at least 8.1 HSPF2 with 15.2 SEER2, and non-ducted at least 8.5 HSPF2. If you live where hard freezes are common, these numbers, especially the 70% capacity retention at 5F, matter more than a high SEER2 alone.
Frequently asked questions
What is the minimum SEER2 for a heat pump?
Carrier notes the DOE requires a minimum of 14.3 SEER2 for residential air-source split systems as of 2023, along with a 7.5 HSPF2 minimum for heating.
What SEER2 counts as high efficiency?
Carrier states models rated 17 SEER2 and above are considered high efficiency, with some reaching up to 22 SEER2. For heating, above 9 HSPF2 is high-efficiency, up to 10.5 HSPF2.
What does ENERGY STAR require?
For standard split-system heat pumps, ENERGY STAR requires at least 7.8 HSPF2, 15.2 SEER2, and 11.0 EER2, which is above the federal minimum.
What is EER2?
It is a third efficiency rating measuring cooling performance at a fixed high outdoor temperature rather than across a whole season. ENERGY STAR standard split systems require at least 11.0 EER2.
Do cold climates need different numbers?
Yes. ENERGY STAR Cold Climate models must post a COP at 5F of at least 1.75 and retain at least 70% of capacity at 5F versus 47F, plus higher HSPF2 thresholds.