**Coefficient of performance (COP), is an expression of the efficiency of a heat pump. When calculating the COP for a heat pump, the heat output from the condenser (Q) is compared to the power supplied to the compressor (W).**

Coefficient of performance (COP), is an expression of the efficiency of a heat pump. When calculating the COP for a heat pump, the heat output from the condenser (Q) is compared to the power supplied to the compressor (W).

The formula to the right can be used to calculate COP.

In other words, COP is defined as the relationship between the power (kW) that is drawn out of the heat pump as cooling or heat, and the power (kW) that is supplied to the compressor.

For example:

A given heat pump used for air cooling has a COP = 2. This means that 2 kW of cooling power is achieved for each kW of power consumed by the pump’s compressor.

COP is indicated without units. Therefore the produced heat and the supplied power employ the same units during COP calculation.