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Heat pump electricity cost calculator

Estimate the electricity demand and running costs of a heat pump – from your heat demand or from your existing heating system’s consumption.

The amount of heat the building needs per year. It is in the energy certificate or follows from your previous consumption.

Heat pump

Measured values from German field trials: air source 3.4 on average with a range of 2.6 to 4.9, ground source 4.3 on average with 3.6 to 5.4. With radiators only and a high flow temperature 2.85 was measured, with underfloor heating 3.70.

Household electricity averaged 37.0 ct/kWh in 2026. Heat pump tariffs are lower: 24 ct/kWh on average with a second meter, 31.5 ct/kWh without. In return they require a second meter and often grid operator control.

Measured on heat pumps in existing buildings it is around 19 %. The calculator only splits the heat demand with it; it uses the same seasonal performance factor for hot water as for heating, which tends to understate the hot water share.

A separate heat pump meter typically costs €50 to €100 gross per year under § 30 MsbG. Enter only what is charged on top.

Measured in German field trials: 1.3 % on average for air source, 0.1 % for ground source. Considerably more in cold years and during failures. Enter 0 if there is no immersion heater.

Comparison with the existing heating

The comparison appears only if you enter the price of your previous fuel. It puts pure fuel costs against pure electricity costs.

Price per kWh of gas (€)

Everything you enter stays in your browser.

Three seasonal performance factors

How the calculator works

  • Electricity demand (kWh) = heat demand (kWh) ÷ seasonal performance factor. With an immersion heater: electricity = heat demand ÷ ((1 − heater share) × factor + heater share). From fuel consumption: heat demand = consumption × calorific value per unit × annual efficiency.
  • The seasonal performance factor is the ratio of heat delivered to electrical energy taken in over a whole year. It depends on the building, flow temperature, heat source, climate and system design and is not a fixed appliance property.
  • The factor comes from field measurements and applies to the generation side. If distribution and hot water preparation are included, the system factor is around 15 % lower on average.
  • The annual efficiency of an old heating system is not a constant. For constant-temperature boilers it falls sharply with load, most of all in summer when only hot water is produced. A blanket 85 % often overstates an old system.
  • This calculator is for running cost orientation only. It is not a heat load calculation, grant advice or system sizing. Investment, servicing, chimney sweep, meter cabinet and a possible radiator replacement are not included.
Worked example

15,000 kWh heat demand, seasonal performance factor 3.5, electricity price €0.28/kWh, standing charge €120 per year, no immersion heater: electricity demand is 4,286 kWh. Pure electricity costs are €1,200.00, with the standing charge €1,320.00 or €110.00 per month.

Frequently asked questions

Which seasonal performance factor should I enter?

If you have no measurement, use the range from field trials: air source 3.4 on average, ground source 4.3 on average. With radiators only and a high flow temperature 2.85 was measured, with underfloor heating 3.70. The calculator shows you three values side by side.

Why does the calculator separate out the immersion heater?

Because part of the electricity does not run through the heat pump but becomes heat directly in the immersion heater. The calculator counts that part at a factor of one instead of the seasonal performance factor. Without that split the electricity demand would come out too low.

How do I know my heat demand?

From the energy certificate, from a heat load calculation or from your previous consumption. In the second mode the calculator derives it from fuel consumption and the annual efficiency of your old system.

Does this replace a heat load calculation?

No. The calculator only estimates running costs. Whether a heat pump suits the building, what output is needed and which radiators must be replaced can only be clarified by an on-site check by a qualified planner.

Where the defaults come from

The values are dated and are not updated automatically. Check them and replace them with your own figures.

  • Seasonal performance factors: Fraunhofer ISE, WP-QS im Bestand project, final report of 25 Nov 2025, 77 systems, measurement 2021 to 2024. Air source 3.4 on average with a range of 2.6 to 4.9, ground source 4.3 on average with 3.6 to 5.4. IWU Darmstadt states 3.05 for radiators only and 3.70 for underfloor heating in its report of 14 Oct 2025.
  • Calorific values: § 9 (3) of the Heating Costs Ordinance gives 10 kWh per cubic metre of natural gas H and 10 kWh per litre of heating oil EL as fallback values. Values in your own billing documents take precedence.
  • Annual efficiencies: Recknagel/Sprenger/Schramek, 2001 edition, tables 5 to 7, based on calorific value. Gas condensing 0.97, oil condensing 0.91, low temperature 0.92 and 0.90, constant temperature 0.83 and 0.81 at medium load.
  • Electricity prices: the BDEW electricity price analysis 08/2026 gives 37.0 ct/kWh for household electricity at 3,500 kWh. Consumer advice centre NRW evaluated heat pump tariffs on 20 Feb 2026: 24 ct/kWh and €140 standing charge on average with a second meter, 31.5 ct/kWh and €200 without.
  • Immersion heater share: Fraunhofer ISE, WP-QS im Bestand, 25 Nov 2025. Share of electrical work: 1.3 % for air source, 0.1 % for ground source. The share of delivered heat is considerably smaller.
  • Hot water share: 19 % of delivered heat, measured on 61 air-to-water heat pumps in existing buildings (Fraunhofer ISE, 25 Nov 2025). The Federal Environment Agency gives 19.3 % final energy for private households in 2024.

Disclaimer

All information is provided without guarantee. The results of this calculator are a non-binding estimate and serve for guidance only. We accept no liability for incorrect, incomplete or wrongly transmitted input, or for the results calculated from it. Terms of Use