COP and JAZ of a heat pump

The theoretical efficiency of a heat pump is described by the COP value (coefficient of performance). The COP value refers to the thermal efficiency of heat pumps in a certain constant operating point. Since the operating point of a heat pump shifts depending on the weather, the COP can only be measured in the laboratory under optimal conditions.

"What exactly does the COP value of eg 4 tell me?"

This simply means that you get a heating power of 4 kW for 1 kW electric drive power.

COP = useful power / electrical drive power

A high COP also leads to a high annual work rate. For the calculation of the COP value, however, only the heat pump alone is considered. For the calculation of the annual working load JAZ, the complete heating system incl. Possibly existing hot water generation, additional electrical consumers such as pumps, the user behavior and the weather conditions over a whole year are considered.

It can therefore be said that the higher the COP or the JAZ, the more energy efficient the heating system.