HSPF2 (Heating Seasonal Performance Factor 2) is the federal standard for measuring heat pump heating efficiency, updated in 2023 to replace the original HSPF metric. It measures how much heat a heat pump delivers per unit of electricity consumed over a heating season.
Like SEER2, HSPF2 uses a revised testing procedure that better reflects real-world conditions. HSPF2 ratings are approximately 15% lower than equivalent HSPF ratings for the same equipment.
The federal minimum HSPF2 for split-system heat pumps is 7.5 (as of 2023). High-efficiency heat pumps achieve 9-11+ HSPF2. A higher HSPF2 means lower heating costs during cold months.