Heat Pump vs Gas or Oil Cost Calculator
Compare the yearly running cost of a heat pump with a gas or oil boiler from your heat demand (or last year's fuel use), the heat pump's COP, your electricity and fuel prices and the boiler's efficiency. See each yearly cost, the difference and the COP at which they break even.
Frequently asked questions
What COP should I use?
Use the seasonal COP (SCOP or SPF), not the headline COP on a data sheet, which is measured in mild test conditions. Air-source heat pumps in a well-insulated home with low-temperature radiators or underfloor heating typically reach about 3 to 4 over a year; older radiators and cold climates push it toward 2.5. Ground-source systems often reach 4 or more. The break-even COP shown tells you what you need to beat.
Why does the boiler efficiency matter?
A boiler turns only part of its fuel into heat: older ones about 70 to 80 %, modern condensing boilers about 85 to 95 %. The fuel you pay for is the heat you need divided by this efficiency. If you start from last year's fuel use, the heat demand is that fuel times the efficiency, so a wrong efficiency changes the answer.
How do I use last year's fuel use?
Choose the unit on your bill: kWh, cubic metres of gas or litres of oil. The tool multiplies by the energy in one unit: about 10.5 kWh per m³ of gas and 10 kWh per litre of oil are typical, but gas varies by country and supplier, so check your bill and edit the figure. Weather varies from year to year, so a cold year overstates the demand.
Does this include the cost of installing a heat pump?
No. It compares running costs only. Divide your quote, after any grants, by the yearly difference for a simple payback time. Servicing and standing charges can be added in the optional yearly fields. The comparison also leaves out price changes over the years, which can swing the result: keep an eye on the ratio of electricity to fuel prices.
Why is the heat pump sometimes not cheaper?
Heat pumps win when electricity is not much more than about three times the price of the fuel's energy, because they deliver three or four units of heat per unit of electricity. With cheap gas and expensive electricity, or a low COP, the boiler can cost less to run. The break-even COP shows exactly where that line falls for your prices.