Heat pump electricity use: what determines consumption

Short answer

A heat pump uses electricity and moves heat from air, ground or water. You calculate yearly electricity use as heat demand divided by the Jahresarbeitszahl.

RECOMMENDED PROVIDERS

How the Jahresarbeitszahl sets electricity use

The Jahresarbeitszahl JAZ is heat over a year divided by electricity including auxiliary energy. A JAZ of 4.0 delivers 4 kWh of heat from 1 kWh of electricity. Values of 4.0 or higher count as ideal at the Umweltbundesamt.

Air-source heat pumps reach this ideal value of 4.0 only in favourable conditions. The COP figure alone is not enough, because it shows only a laboratory point.

What determines use in your house

Low heat demand and a low flow temperature reduce electricity use. A surface heating system works at 35 °C or less. Ground and groundwater stay more stable in winter than cold outdoor air.

The built-in heating rod stays switched off in normal operation. An undersized unit uses the heating rod more often on cold days.

PROVIDERS

How you check consumption

Most heat pumps have a heat meter for the heat they deliver. You divide those kWh by the heat-pump electricity in the same period. The result is the measured Jahresarbeitszahl for your operation. Compare that measured value with the planning documents of the system.

Law and funding

The Gebäudemodernisierungsgesetz has applied nationwide since 29 July 2026. There is no duty to replace a working heating system. A heat pump is one permitted option, not the only one.

KfW funds the installation in existing homes through product 458. Federal funding for efficient buildings requires a planned minimum Jahresarbeitszahl. You file the funding application before you award the contract to the firm.

An energy consultant calculates heat demand and Jahresarbeitszahl for your building. The overview of iSFP and costs sits in the energy-consultant tip. Selected heat-pump providers sit in the provider list.