Definition
HSPF2 (Heating Seasonal Performance Factor 2) is the U.S. Department of Energy rating for how much heat a heat pump delivers per watt-hour of electricity over a typical heating season, measured under the M1 test procedure adopted in 2023. Since January 1, 2023, new split-system heat pumps nationwide must be rated at least 7.5 HSPF2.
Also called: Heating Seasonal Performance Factor 2, HSPF
Why it matters to you
SW Washington and the Portland metro are heating-dominant, so for most local heat pump owners HSPF2 describes the bigger share of the year's HVAC electricity. By rating arithmetic, a 9.0 HSPF2 heat pump uses about 17% less electricity than a 7.5 HSPF2 one for the same heating (1 − 7.5/9.0).
Practical guidance
Compare HSPF2 and SEER2 together from the AHRI Directory listing for the exact matched system on your quote. Also ask how much heating capacity the heat pump keeps at cold temperatures and when backup heat turns on, because the seasonal rating does not show performance during an east-wind freeze.
How HSPF2 options compare
| HSPF2 rating | Where it sits | Heating electricity vs. 7.5 HSPF2 for the same heat (1 − 7.5/x) |
|---|---|---|
| 7.5 | Federal minimum, split-system heat pumps | Baseline (0%) |
| 8.0 | Above the minimum | About 6% less |
| 8.5 | Mid-efficiency tier | About 12% less |
| 9.0 | Higher-efficiency tier | About 17% less |
| 10+ | High-efficiency tier, typically variable-speed | About 25% less at 10; more above 10 |
What is the minimum HSPF2 for a new heat pump in Washington or Oregon?
The federal minimum for a new split-system heat pump is 7.5 HSPF2, and it applies nationwide, including WA and OR, for equipment made on or after January 1, 2023. The same heat pump must also meet the 14.3 SEER2 cooling minimum. Packaged heat pumps have a separate 6.7 HSPF2 minimum.
How much does a higher HSPF2 cut heating electricity?
The rating arithmetic is 1 − (7.5 ÷ new HSPF2) for the same heating load. That gives about 6% less at 8.0, about 12% less at 8.5, about 17% less at 9.0 and 25% less at 10. These are ratios of ratings, not bill estimates; ductwork, thermostat habits and backup-heat use change real results.
Should Pacific Northwest homeowners prioritize HSPF2 or SEER2?
For most SW Washington and Portland-metro homes, HSPF2 deserves the most weight on a heat pump, because the heating season is long and the cooling season is short. SEER2 still matters if your home overheats in summer heat waves. Look at both on the AHRI listing for the matched system.
Does HSPF2 tell me how a heat pump handles a hard freeze?
Not fully. HSPF2 is a seasonal average, while cold-snap comfort depends on how much capacity the unit keeps at low temperatures and when backup heat takes over. ENERGY STAR certification requires third-party verified low-temperature testing down to 5°F, so ask for low-temperature capacity data alongside the HSPF2 rating.
Is HSPF2 the same as the old HSPF rating?
No. HSPF2 uses the newer M1 test procedure, so the same heat pump scores lower in HSPF2 than in the older HSPF. That is why today's 7.5 HSPF2 minimum looks lower than older HSPF figures without being a weaker standard. Compare HSPF2 only with HSPF2.
About this definition
Written by the Home Energy Group team — a family-owned HVAC company celebrating 25 years of comfort & care across SW Washington and the Portland metro, licensed in Washington (WA LIC# HOMEEGI003J7) and Oregon (OR CCB# 184255). Definitions inform; an on-site diagnosis decides.
