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UNITED STATES · EFFICIENCY & BILLS

HSPF2 and COP: read a heat pump heating specification

By SAVPWR Editorial · Published · 2 min read

For U.S. residential systems. General education, not a site diagnosis or engineering certification.

THE DIRECT ANSWER

What is the difference between HSPF2 and COP?

HSPF2 is a seasonal heating rating in Btu per Wh. COP is a dimensionless ratio of delivered heat to electrical input at stated conditions. Do not use a seasonal label as the COP on the coldest night.

Start with the denominator

HSPF2 combines heating output and electrical consumption over a standardized season. COP compares input and output using the same energy units. The ENERGY STAR criteria distinguish seasonal heating performance from low-ambient COP and capacity requirements. [1]

Capacity and efficiency must travel together

A unit can have an appealing COP at one temperature while lacking enough heating output for your house at another. Ask for maximum and minimum output and input at relevant temperatures, including the local winter design condition. Identify whether backup heat is included in the operating scenario. [2]

Build an honest cost comparison

Use local energy prices and an operating-period COP assumption that suits the question. A point COP is useful for a point cost comparison; seasonal household costs require weather, load and backup-energy assumptions. State which type of calculation you are making.

PUT IT TO WORK

Decision exercise

At an assumed COP of 3, one purchased kWh delivers 3 kWh of heat, about 10,236 Btu using 3,412 Btu/kWh. At $0.24/kWh, that heat costs $0.08 per delivered kWh. These are arithmetic assumptions, not a claim that a particular unit maintains COP 3 in all weather.

Any numbers in this exercise are illustrative assumptions, not product performance, an installed quote or a personal savings estimate.

What to bring to the conversation

  • Collect HSPF2 plus temperature-specific performance tables.
  • List the backup-heating type and control settings.
  • Separate point-condition and seasonal results.

One more useful distinction

Can HSPF2 be divided by 3.412 to estimate a seasonal ratio?

The unit conversion gives a seasonal energy ratio under the rating test. It does not establish the COP at any particular outdoor temperature.

Sources and verification

Technical statements draw on the linked references. Decision exercises and comparison frameworks are SAVPWR’s own explanatory examples. Current rules and program availability should be rechecked before a purchase.

  1. ENERGY STAR — Heat Pump Equipment Key Product CriteriaSource checked 2026-11-09 · External primary reference
  2. PNNL — Cold Climate Heat Pump Sizing and SelectionSource checked 2026-11-09 · External primary reference

AI-assisted preparation; checked against public sources. These articles have not received a licensed HVAC professional’s review. Read our editorial policy.

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