Heating seasonal performance factor. It folds in performance at several outdoor temperatures, defrost losses and backup strip heat over a modeled heating season. Dividing HSPF by 3.412 gives an approximate seasonal COP. HSPF2 is tested at higher external static pressure and reads lower than HSPF for the same equipment. Cold-climate buyers also look at rated capacity at 5 degrees F, which HSPF alone hides.
Both units are 9 HSPF2, but only the cold-climate one holds full capacity at 5 degrees, that's the one for this town.
Also heard as
- heating seasonal performance factor
Related terms
SEER
Seasonal energy efficiency ratio: an air conditioner's cooling output over a typical season divided by its electricity use.
COP
Coefficient of performance: heat moved or delivered for each unit of energy put in, with both measured in the same units.
Heat pump
A refrigeration system that can reverse its flow to move heat indoors in winter as well as outdoors in summer.
Defrost
A cycle that melts frost off a heat pump's outdoor coil or a refrigerated evaporator so it can keep moving heat.