HSPF
Heating Seasonal Performance Factor — the standard rating for heat pump heating efficiency.
Definition
HSPF stands for Heating Seasonal Performance Factor, the standardized measure of heat pump heating efficiency over a typical season. It is the ratio of total heating output (in BTU) to total electricity input (in watt-hours) over the heating season. Higher HSPF means more heat per unit of electricity. Federal minimum HSPF for new residential heat pumps is 8.8 (HSPF2 7.5 under the new test methodology). Premium variable-speed heat pumps reach HSPF 12-14, delivering substantially better cold-weather performance and lower operating cost.
Where this term appears
HSPF comes up in product spec sheets, service reports, and troubleshooting documentation across most major appliance brands. If you encountered it in a manual or a service description and want context for how it fits into the larger picture, the related articles in the sidebar drill into the practical details. The glossary as a whole is intended as a quick lookup reference; for a deep dive on any specific topic, jump to the related buying guide or troubleshooting article.