Heat Pump vs Gas Boiler: Which Is Cheaper to Run?
It’s the question every homeowner weighing a heat pump asks, and the honest answer is: it depends on one thing more than any other — the ratio between your electricity price and your gas price. Here’s how to work out the answer for your own home rather than relying on a generic claim.
Why a heat pump can win despite electricity costing more
A gas boiler burns fuel and is perhaps 85–90% efficient — you get a bit less than one unit of heat per unit of gas. A heat pump doesn’t make heat, it moves it, delivering roughly 3 units of heat per unit of electricity (a “COP” of about 3). So even though electricity usually costs 2–4× more than gas per kWh, the heat pump’s 3× efficiency can more than cancel that out.
The break-even maths in plain terms
A heat pump is cheaper to run when:
electricity price ÷ gas price < heat pump COP × boiler efficiency
For example, with a COP of 3 and a boiler at 85% efficiency, the heat pump wins as long as electricity costs less than about 2.55× your gas price. In many regions it does; in places with very cheap gas and pricey electricity, it may not. Rather than do this by hand, plug your real prices into the heat pump savings calculator — it tells you the annual difference directly, and will honestly show a negative saving if gas wins at your prices.
What tips the balance
Your local energy prices
The single biggest factor. Cheap electricity (or expensive gas) strongly favours a heat pump. Use the gas vs electric heating calculator to see resistance-electric vs gas, then the heat pump calculator for the COP advantage.
The heat pump’s real-world COP
Cold weather lowers a heat pump’s efficiency. A well-installed modern unit averages a COP around 3, but a poorly sized one in a cold climate may do worse — which narrows the saving.
Your home’s insulation
Heat pumps work best in homes that hold heat well. Improving insulation first lifts the COP you actually achieve — estimate the payback with the insulation savings calculator.
Don’t forget the upfront cost
Running cost is only half the picture. Heat pumps cost more to install, though incentives can close the gap. Weigh the install cost against the yearly running saving to find your payback — the same break-even logic as our solar payback calculator applies.
The bottom line
A heat pump is usually cheaper to run than a gas boiler where electricity isn’t hugely more expensive than gas — which is most places. The only way to know for your home is to enter your actual prices into the heat pump savings calculator and see the number. Don’t take a brochure’s word for it; check the maths.