Heat Pump COP Calculator
Calculate the coefficient of performance (COP) of a heat pump or refrigeration system.
Compare to Carnot COP and estimate energy savings.
The Coefficient of Performance (COP) measures how efficiently a heat pump or refrigerator works:
Heat pump (heating mode): COP_heating = Q_hot / W = Heat delivered / Electrical work input
Refrigerator/air conditioner (cooling mode): COP_cooling = Q_cold / W = Heat removed from cold space / Work input
The relationship between heating and cooling COP: COP_heating = COP_cooling + 1
Maximum possible COP (Carnot): COP_heating_max = T_hot / (T_hot − T_cold) COP_cooling_max = T_cold / (T_hot − T_cold)
What does COP mean in practice?
A COP of 3.5 for heating means: for every 1 kW of electricity consumed, the heat pump delivers 3.5 kW of heat to your home.
Compare to:
- Electric resistance heater: COP = 1.0 (converts electricity to heat directly)
- Heat pump (air source, mild climate): COP = 2.5–5.0
- Heat pump (ground source): COP = 3.0–6.0
This is why heat pumps are far more efficient than electric heaters — they “move” heat rather than generating it.
Energy efficiency rating:
- SEER (Seasonal Energy Efficiency Ratio): cooling rating for AC units (SEER = 12 ≈ COP = 3.5)
- HSPF (Heating Seasonal Performance Factor): heating rating
- EER = BTU/(Wh) = COP × 3.412 for cooling
How we build and check this calculator
This calculator runs entirely in your browser, so the numbers you enter stay on your device. The math behind it is written by hand and tested against worked examples and standard references before the page goes live.
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