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CALCULATOR · Finance

Heat Pump vs Gas Calculator

The same year of heat priced on both meters — gas boiler against heat pump, with the break-even tariffs.

Show formula
gas = heat ÷ boiler efficiency × gas price · heat pump = heat ÷ SCOP × electricity price · savings = gas − heat pump · month = year ÷ 12

Inputs

Useful heat the home needs across a heating year, in kWh — a gas bill converts at roughly 10.5 kWh per m³, an energy assessment states it directly, and the gas heating calculator estimates it from the building.

What one kWh of gas costs on your bill. A meter reading in m³ or therms converts first: 1 m³ ≈ 10.5 kWh, 1 therm = 29.3 kWh.

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A modern condensing gas boiler is 90–96%, an older non-condensing one 70–80%. Combustion never exceeds 100%.

Your price for one kWh of electricity — the tariff the heat pump's meter actually pays, night rate included if the unit mostly runs off-peak.

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Seasonal COP: kWh of heat delivered per kWh of electricity over the whole year. Air-source units sit at 2.5–3.0 through a cold winter, 3.5–4.5 in milder climates or ground-source.

Result

Your result appears here

Enter Heat needed per year and the result fills in as you type.

How it works

  1. Enter the useful heat your home needs across a heating year, in kWh — the figure a gas bill, an energy assessment or the gas heating calculator gives you. Both systems are priced against this same heat.
  2. Fill in the gas side: your price per kWh and, if you know it, the boiler’s seasonal efficiency. Then the heat pump side: your electricity tariff and, if you know it, the unit’s SCOP.
  3. Read what the same winter costs on each meter — plus the two per-kWh-of-heat rates and the break-even prices at which the systems would tie.

Frequently asked questions

Where do I find my yearly heat demand?

Three places, roughly in order of trust: an energy assessment states it directly; a year of gas bills gives it back — multiply the metered kWh by the boiler efficiency to undo the losses, or convert m³ at about 10.5 kWh each first; and the gas heating calculator estimates it from the building itself. The figure is the one input that moves both sides equally, so a rough estimate still prices the comparison honestly.

What does the break-even electricity price mean here?

It is the tariff at which the heat pump’s year costs exactly what the boiler’s does, given the gas price and the two efficiencies you entered. Below it the heat pump wins the winter; above it the boiler does. It does not depend on how much heat you need — both bills scale with the house — and it moves sharply with the SCOP, which is why a poorly matched or cold-sited unit flips the answer.

Does this include installation cost, grants and standing charges?

No — this is the energy bill only, the piece that repeats every winter. A heat pump usually costs far more to install than a boiler, grants change that by country, and daily standing charges sit outside both meters here. Use the yearly figure as the running-cost line in your payback sums, then add the one-time costs and fixed charges separately.

Examples

18,000 kWh of heat in a year: an 85% gas boiler at 0.09 per kWh against a heat pump at SCOP 3.6 on a 0.25 tariff
21,176.47 kWh and 1,905.88 of gas against 5,000 kWh and 1,250.00 of electricity — the heat pump is cheaper by 655.88 a year (34.4%), and stays ahead up to a tariff of 0.381 per kWh (or down to gas at 0.059).
25,000 kWh in a cold climate: a 90% boiler at 0.06 per kWh against SCOP 2.8 on an expensive 0.35 tariff
27,777.78 kWh and 1,666.67 of gas against 8,928.57 kWh and 3,125.00 of electricity — the boiler is cheaper by 1,458.33 a year; the tariff would have to fall to 0.187 per kWh before the heat pump drew level.

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