Coefficient of Performance (COP) Calculator
Calculate the coefficient of performance (COP) of a refrigerator or heat pump. COP is the useful heat moved divided by the work input, so a higher number means a more efficient system.
How to calculate the coefficient of performance
- Choose cooling for a refrigerator or air conditioner, or heating for a heat pump.
- Enter the heat transferred in joules (Qc removed for cooling, or Qh delivered for heating).
- Enter the work input in joules.
- Read the COP, which is the heat moved per unit of work.
Examples
Refrigerator (cooling)
Qc = 3000 J, W = 1000 J
COP = 3
Heat pump (heating)
Qh = 4000 J, W = 1000 J, heating
COP = 4
Frequently asked questions
What is the coefficient of performance formula?
COP = heat transferred / work input. For cooling, use the heat removed from the cold space (Qc). For heating, use the heat delivered to the warm space (Qh). Both use the same work input W.
What is a good COP value?
Typical air conditioners and refrigerators have a cooling COP around 2 to 4, while air source heat pumps often reach a heating COP of 3 to 5. Higher is more efficient.
Why can COP be greater than 1?
COP is not an efficiency capped at 1. A heat pump moves existing heat rather than creating it, so it can deliver several times more heat energy than the electrical work it consumes.
How are heating and cooling COP related?
For the same machine, the heating COP equals the cooling COP plus 1, because the heat delivered equals the heat removed plus the work input (Qh = Qc + W).
What is the difference between COP and EER?
COP is dimensionless and uses SI units. EER (energy efficiency ratio) expresses cooling output in BTU per hour divided by input in watts, so it is about 3.41 times the cooling COP.
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