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Heat pump consumption

Use heat demand and COP to estimate electrical power, kWh and running cost.

✓ Editable COP✓ Monthly consumption✓ Annual cost

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Demand, efficiency and usage

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LearnUnderstand COP and consumptionRead related guide →

Indicative diagram of this calculator inputs — Distinguish thermal output, COP and electrical energy consumption.

How we calculate consumption

We divide heat demand by COP to estimate average electrical power, then multiply by hours, days and the price per kWh.

Thermal kW ÷ COP × hours × days × €/kWh

COP and SCOP are not the same

COP describes specific conditions; SCOP summarises a standard season. For a monthly estimate, use a conservative figure suited to the climate and flow temperature.

Consumption is not constant

Inverter units modulate and may run for many hours at low power. This calculator represents an average demand, not maximum electrical draw.

How to choose a realistic COP for this calculator

COP is not a fixed property of a heat pump. It changes with outdoor temperature, indoor setpoint, flow temperature, humidity, defrost operation and part-load behaviour. Using the best laboratory COP for every hour of the month can therefore underestimate electricity use.

Use a conservative average for the period you are estimating

If you have manufacturer performance tables, look for conditions close to your climate and operating temperature. For a monthly estimate, use an average COP that reflects colder periods and defrost rather than only mild-weather performance.

Heat demand is just as important as efficiency

A very efficient heat pump can still consume significant electricity if the building loses a lot of heat or the thermostat is set high for many hours. Insulation, air leakage, room size and outdoor conditions all affect the thermal demand entered in the calculator.

Compare the estimate with measured data

After several representative days, compare the calculated kWh with actual consumption and adjust the assumed COP or operating hours. The guide on heat pump consumption explains the variables in more detail.

If you are deciding between systems, see electric radiator vs heat pump. For Spain, replace the default tariff with the current electricity price.

Editorial review: 11 Oct 2026. This calculator is an estimate, not a substitute for a building heat-loss calculation or manufacturer performance data.