Heat Pump Running Cost Calculator

How to use this calculator

1. Pick your country. This preloads the local electricity price and, importantly, the heating fuel you would actually be competing with — district heating in Sweden, Finland and Denmark, gas in Germany and the UK, coal in Poland, and so on.
2. Enter your annual heat demand in kWh. If you heat with gas, your annual gas usage is a good proxy.
3. Enter the heat pump's SCOP (seasonal coefficient of performance — the honest, whole-year figure, not the lab number on the box).
4. Adjust the price and efficiency of your current system, add the install cost and any grant, and click Compare running costs.

The only honest way to compare heating systems

Comparing the price of electricity to the price of gas is meaningless, because they buy different amounts of heat. Gas at 11 c/kWh burned in a 90%-efficient boiler delivers a kilowatt-hour of heat for 12.2 c. Electricity at 30 c/kWh through a heat pump with a SCOP of 3.2 delivers the same kilowatt-hour of heat for 9.4 c. The expensive fuel wins.

For a heat pump, the "efficiency" is the SCOP — a SCOP of 3.2 means 320% efficiency, because the pump moves heat rather than making it. That single conversion is what separates this calculator from the ones that just compare headline fuel prices.

The break-even SCOP — the number to remember

The result gives you a figure like 2.6. It means: at your electricity price and your current fuel price, a heat pump needs to average at least a SCOP of 2.6 across the whole year to cost less to run than what you have now. Below that, it costs you more.

This matters because it is a test you can apply to any quote. A modern air-to-water heat pump in a well-insulated house with underfloor heating realistically achieves a SCOP of 3.5–4.5. The same unit in a poorly insulated house with small, hot radiators may only manage 2.5. If your break-even SCOP is 3.4 and your house is the second kind, the honest answer is that a heat pump will not save you money until you improve the emitters or the insulation.

Radiator temperature is the lever. Every 5 °C you can drop the flow temperature adds roughly 10–15% to the SCOP.

Gas is not the enemy everywhere

Most heat-pump calculators on the internet compare against a gas boiler, because they were written for Germany or the UK. That comparison is meaningless in much of Europe:

• Sweden, Finland, Denmark: gas boilers barely exist. The real competitor is district heating (fjärrvärme, kaukolämpö, fjernvarme), which is metered as delivered heat and therefore close to 100% efficient at the point of use — a much tougher benchmark than a gas boiler.
• Norway: oil heating has been banned since 2020 and there is no gas grid. The competitor is direct electric heating, which means the heat pump's saving is simply (1 − 1/SCOP) — around 70% at a SCOP of 3.3.
• Poland: coal is still widely burned in older houses, at low efficiency but low cost.
• Denmark, 2026: the electricity tax was cut to almost nothing, which changed the arithmetic so much that older Danish comparisons now give the wrong answer.

This calculator preloads the fuel that is actually relevant for your country, and lets you change it.

Frequently asked questions

What is SCOP and why not COP?

COP is the efficiency at one operating point, usually a flattering one. SCOP is the seasonal average across a whole heating year, including the cold days when the pump works hardest. Manufacturers quote both; only SCOP predicts your bill.

What SCOP can I realistically expect?

An air-to-water heat pump in a well-insulated home with underfloor heating: 3.5–4.5. The same unit with old high-temperature radiators: 2.5–3.0. Ground-source: 4.0–5.0. Air-to-air units in a mild climate can be higher still.

How do I find my annual heat demand?

If you heat with gas, use your annual gas consumption in kWh — your bill states it. For oil, multiply litres by about 10 kWh. For pellets, kilograms by about 4.8 kWh. For district heating, the bill is already in kWh or GJ (1 GJ = 278 kWh).

Is a heat pump cheaper than district heating?

Sometimes, and it is a much closer contest than the gas comparison. District heating is billed as delivered heat, so its effective efficiency is near 100%. A heat pump needs a genuinely good SCOP and a competitive electricity price to beat it — which is exactly what the break-even figure in this tool tells you.

Does the calculator include maintenance and the standing charge?

No — it compares running cost and pays back the installation. Both systems have service costs, and if you drop a gas connection you also drop its standing charge, which improves the heat pump's case. Add that separately if it matters to you.

Why is my payback so long?

Usually because the install cost is high relative to the saving. Grants change this substantially, which is why the grant field is there. Also check the break-even SCOP: if it is close to the SCOP you expect, the running-cost saving is thin and no payback period will look good.