Heat pump running costs compared with a gas boiler

Checked November 2026

At the current price cap a well set up heat pump costs about the same as a gas boiler to run, or a bit less. In our estimate below, a heat pump with an efficiency (SCOP) of about 2.8 breaks even with an 85% efficient gas boiler. Above that it comes out cheaper. Below it, dearer. A cheaper heat pump tariff moves the numbers further in its favour.

That’s an estimate, not a promise. Your own costs depend on your house, your heat pump and what you pay for electricity.

How do you work out heat pump running costs?

You need three numbers.

How much heat your home uses in a year. The easiest way to get this is from your gas bills. Take your yearly gas use in kWh and multiply it by your boiler’s efficiency. A typical older boiler might turn 85% of the gas into heat.

How efficient the heat pump is over the year. This is the SCOP, or seasonal coefficient of performance. A SCOP of 3 means the heat pump gives out 3 kWh of heat for every 1 kWh of electricity it uses, averaged across the year. It’s higher in mild weather and lower in a cold snap.

What you pay for electricity. On a standard tariff that’s the price cap rate. On a heat pump or time of use tariff it can be a lot less for part of the day.

Then the sum is simple. Heat needed divided by SCOP gives you the electricity used. Multiply that by your unit rate.

For example, if your home needs 9,775 kWh of heat a year and the heat pump runs at a SCOP of 3, it uses about 3,258 kWh of electricity. At 26.32p a unit, that’s about £858.

How do heat pump and gas boiler running costs compare?

Here’s how that plays out for a typical home. This table is an estimate. The assumptions are listed straight under it.

Estimate, Oct to Dec 2026 price cap	Yearly heating cost	Compared with gas
Gas boiler, 85% efficient	£917
Heat pump, SCOP 2.5	£1,029	about £113 more
Heat pump, SCOP 3.0	£858	about £59 less
Heat pump, SCOP 3.5	£735	about £181 less
Heat pump, SCOP 4.0	£643	about £273 less

What we assumed:

• Gas use: 11,500 kWh a year. That’s the average household gas use Which? used in its 2025 heat pump calculator.
• Boiler efficiency: 85%, also the figure Which? used. So the home needs about 9,775 kWh of heat a year.
• Gas price: 7.97p per kWh. Ofgem price cap, 1 October to 31 December 2026, Direct Debit, average across England, Scotland and Wales, including 5% VAT.
• Electricity price: 26.32p per kWh. Same Ofgem cap and period. This rate has no VAT on it, because the government has removed VAT from electricity bills from 1 October 2026 to 31 March 2027.
• Heat pump efficiency: SCOP 2.5 to 4.0. These are example figures to show the range, not measured results. Which? used 3.0 and 4.0 in its own examples.
• Standing charges: left out. You pay the electricity standing charge either way. If you have the gas supply capped off after the install, you also stop paying the gas standing charge of 29.68p a day, which is about £108 a year at the current cap.
• Hot water: included in the gas figure and treated the same for the heat pump. In practice heat pumps tend to run less efficiently on hot water, so treat this as a rough guide.

Two things to take from this. First, the break even point is a SCOP of about 2.8. A heat pump that’s been designed properly should beat that, but a badly sized one with small radiators and high flow temperatures may not. Second, it’s a small margin either way at SCOP 3. The big swings come from efficiency and tariff, not the box itself.

Running costs are only one part of the choice. Upfront cost, the grant and your house all count, and we compare them side by side in heat pump or gas boiler: which should you choose?

What happens in April 2027. If VAT goes back on electricity at 5% from 1 April 2027 and nothing else changes, the 26.32p rate would become about 27.64p. On our figures the break even point would move up to a SCOP of about 2.95. At SCOP 3 the heat pump would then come out only about £16 a year cheaper than gas. Prices will change before then anyway, so we’ll update this page each quarter.

Why do other sources give different answers?

You’ll see different answers online, and it’s worth knowing why.

The Energy Saving Trust says that on standard tariffs, where electricity is nearly four times the price of gas, a heat pump can cost slightly more to run than a new gas or oil boiler. It also says switching to a heat pump time of use tariff can make it cheaper to run than a gas boiler (EST, page updated October 2026).

Which? found heat pump running costs can match or beat a gas boiler even on standard capped prices, with bigger savings on a time of use or heat pump tariff (Which?, April 2025).

They’re not as far apart as they sound. The EST’s “nearly four times” is a different price gap from today’s cap, where electricity is about 3.3 times the price of gas. The smaller that gap, the easier it is for a heat pump to win.

What changes the running cost?

How does efficiency affect running costs?

The heat pump’s SCOP isn’t fixed. It depends a lot on how the system is designed and set up. The main thing is flow temperature, which is how hot the water going round your radiators is. The lower it is, the more efficient the heat pump. Radiators that are big enough for the room let you run lower temperatures and still stay warm. Our guide on new radiators for a heat pump explains how that’s checked.

That’s why the survey and design matter so much on any air source heat pump installation. A heat pump sized from a proper room by room heat loss calculation, with radiators upgraded where needed, has a much better chance of a good SCOP than one fitted in a hurry.

The EST says running costs depend on whether your radiators are the right size, your electricity tariff and how the heat pump is controlled. We’d agree with all three.

Does a heat pump tariff make it cheaper?

It can. This is the biggest lever you can pull yourself. Heat pump and time of use tariffs charge less for electricity at certain times of day. A heat pump can heat the house and the hot water cylinder in those cheaper windows and coast through the expensive ones.

From the table above, at SCOP 3 the heat pump breaks even with gas at an average of about 28p a unit. Below that, on these assumptions, the heat pump comes out cheaper. Tariffs change often, so compare the current heat pump electricity tariffs on each supplier’s own page before you switch. We’re not an energy broker.

How can I lower my heat pump running costs?

Most of this is free once the heat pump is in.

• Think steady, not blasts. Heat pumps are designed to run at a low, steady temperature. Ask your installer before you set it to switch off and on through the day like an old boiler.
• Use weather compensation. This lets the heat pump lower the flow temperature on mild days. Ask your installer to set it up and explain it.
• Keep the flow temperature low. As low as keeps you comfortable.
• Time the hot water. Heat the cylinder in the cheapest window on your tariff.
• Switch tariff. If you have a smart meter, look at heat pump and time of use tariffs.
• Cap the gas. If nothing else in the house uses gas, capping the supply ends the gas standing charge.
• Insulate. Less heat lost means less heat to make.

Ask your installer to walk you through the heat pump settings before they leave.

Frequently asked questions

Are heat pumps cheaper to run than gas boilers?

At the October to December 2026 price cap, on our estimate, a heat pump with a SCOP above about 2.8 costs less to run than an 85% efficient gas boiler. Below that it costs more. On a heat pump tariff the margin gets better. Your own figure depends on your home and system.

How much electricity does a heat pump use?

It depends on how much heat your home needs. In our example home, which needs about 9,775 kWh of heat a year, a heat pump with a SCOP of 3 would use about 3,258 kWh of electricity for heating and hot water.

Want a running cost estimate based on your own home? Our free home assessment works out your heat loss room by room.

Sources

• Ofgem, “Changes to energy price cap between 1 October and 31 December 2026” (electricity 26.32p per kWh excluding VAT, 54.83p a day; gas 7.97p per kWh including 5% VAT, 29.68p a day; VAT removed from electricity 1 October 2026 to 31 March 2027), checked 3 November 2026, www.ofgem.gov.uk
• Which?, “Heat pump calculator” news article (30 April 2025; 11,500 kWh gas use, 85% boiler efficiency, SCOP 3.0 and 4.0 examples), checked 3 November 2026, www.which.co.uk
• Energy Saving Trust, “Air source heat pumps: costs, savings and benefits” (running costs on standard and time of use tariffs, last updated 20 October 2026), checked 3 November 2026, energysavingtrust.org.uk
• Running cost table: Greenbox Energy estimate, November 2026, worked from the Ofgem and Which? figures above