Heat Pumps & Mini-Splits

What Is COP (Coefficient of Performance)?

Definition

COP is the ratio of heat a heat pump delivers to the electrical energy it consumes to deliver it — a COP of 3 means three units of heat output for every one unit of electricity in. Unlike a furnace's AFUE, which tops out under 100%, COP is routinely well above 1 because the heat pump is moving heat, not manufacturing it from fuel.

Why it matters for your home

A higher seasonal COP directly lowers your winter electric bill for the same heat output — it's the number behind our heating cost calculator's comparison between heat pumps and gas furnaces at your actual utility rates.

What to do about it

COP drops as outdoor temperature drops, so ask for the COP at a cold-weather rating point (not just the best-case number) when comparing heat pump models for our climate.

Money term — the details

Why does COP change with the weather?

The colder it is outside, the harder the heat pump has to work to extract usable heat from the outdoor air, so its efficiency (COP) falls as temperatures drop — this is why cold-climate-rated equipment and backup heat both matter here.

Is COP the same thing as HSPF2?

They're related but not identical — COP is a single-condition efficiency ratio, while HSPF2 is a seasonal average across a full standardized heating season. HSPF2 is what shows up on the equipment label and rebate paperwork.

See it in context Heating Cost Calculator

Sources

Site content — cost-calculator-data.ts (EFFICIENCY_EXPLAINERS)

This definition is pending licensed-trade technical review. It's sourced from our own published service and guide content, not invented — but hasn't yet been signed off by a licensed HVAC reviewer.

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