Heat pump running cost calculator
See what your heating could cost to run each year — your current boiler, a brand-new A-rated gas boiler, and an air source heat pump. Put in your own figures; we pre-fill today's average prices for you.
Compare your running costs
This is an illustration, not a quote. Change any figure to match your own home and bill.
Prices are pre-filled from the latest Ofgem price cap. Edit any figure to match your own bill.
vs. your current boiler. Against a brand-new gas boiler, the heat pump is —.
Figures are an illustration only — not a quote or financial advice. Running costs are calculated from the energy prices and efficiencies you enter, using the standard heat-demand method. Your actual costs depend on your home, its insulation, how the system is designed and run, your region and your tariff.
What actually drives the saving
We'd rather be straight with you than flatter a heat pump with numbers it won't hit. Two things decide whether an air source heat pump is cheaper to run than a boiler:
1. The price of electricity vs gas. Right now a unit of electricity costs roughly 3.5 times as much as a unit of gas. So a heat pump has to be at least about three-and-a-half times more efficient than a gas boiler just to break even on running cost. The good news is that a well-designed heat pump comfortably does that.
2. The SCOP — how efficient the heat pump actually is in your home. SCOP (Seasonal Coefficient of Performance) is how many units of heat the pump delivers for each unit of electricity it uses. A boiler is always under 1 (you never get more heat out than the gas you put in); a heat pump is typically 3 to 5, because it moves heat from the outside air rather than burning fuel — which is how it can be over 100% efficient.
Against an old, tired boiler, a heat pump nearly always wins on running cost. Against a brand-new A-rated gas boiler, it's closer — a heat pump pulls clearly ahead when it's well designed and running at a high SCOP. As MCS-certified and Heat Geek installers, designing for a high SCOP is exactly what we do: low flow temperatures, correctly sized emitters and a proper heat-loss survey for every room.
And remember the £7,500 Boiler Upgrade Scheme grant — that's money off the installation price (which we handle for you), separate from the running-cost figures above.
About SCOP: SCOP (the seasonal average, which sets your annual running cost) depends on many variables — your home's insulation, the radiators or underfloor heating, the flow temperature the system is designed to, the outside weather, your hot-water use and how the system is run. Many systems see a SCOP of 2.8–3.5; a well-designed, low-temperature system — exactly what we aim for as Heat Geek and MCS installers — reaches 4–5, and our very best installs push towards the top of the slider. Higher one-off figures you may have seen are usually COP measured at mild conditions, not the year-round average. The slider lets you try different figures; we'll give you a realistic estimate for your home at survey.
Helpful guides
How are heat pumps over 100% efficient?
The simple physics behind why a heat pump delivers far more heat than the electricity it uses.
Read the guide →How to reduce your energy bills
Practical, no-cost and low-cost ways to cut what you spend on heating and hot water.
Read the guide →Air source heat pumps
How we design and install Vaillant aroTHERM systems — and how the £7,500 grant works.
Learn more →Want a realistic figure for your home?
Book a free, no-obligation survey and we'll estimate the SCOP and running costs for your actual property — and factor in the £7,500 grant where you qualify.