Heat pump running cost UK: cheaper than a gas boiler in 2026?

Heating 8 min read

By the Plug & Penny editorial team · Published 11 November 2026

At the Ofgem price cap for 1 October to 31 December 2026, a typical UK air source heat pump costs about £765 a year to heat a medium home. A new gas boiler doing the same job costs about £757 a year. On a standard tariff, the two are almost level.

The tipping point is a heat pump efficiency (seasonal performance factor, or SPF) of about 2.8 against a new boiler. Above that, the heat pump is cheaper. If you disconnect gas completely, the break-even falls to about 2.5 for the medium home, because you stop paying the gas standing charge.

Yearly heating cost: heat pump vs gas boiler (UK, Oct–Dec 2026)

Prices: electricity 26.32p/kWh and gas 7.97p/kWh, GB average, Direct Debit (Ofgem, 1 October to 31 December 2026). Every row delivers the same 8,075 kWh of heat. Standing charges are left out here and covered further down.

The heat pump rows use efficiencies measured in real UK homes, explained below. The last row shows the cost if a heat pump matched its installer's design forecast. The measured data further down shows how far real installs tend to fall short of that.

How the numbers are worked out

These are calculations from published data, not our own measurements.

The starting point is Ofgem's typical medium household, which uses 9,500 kWh of gas a year. Ofgem cut this from 11,500 kWh in July 2026 (House of Commons Library; Ofgem consultation).

Gas bought is not the same as heat delivered, because boilers lose some energy. The Energy Saving Trust assumes a new gas boiler runs at about 85% and an older one nearer 75% (Energy Saving Trust). So the medium home needs 9,500 × 0.85 = 8,075 kWh of heat.

One limitation: the tables treat all 9,500 kWh as heating and hot water. If you cook on gas, a small part goes on cooking instead. Heat demand, and both the gas and heat pump bills, would then be slightly lower than shown.

The sums:

• Gas boiler: 9,500 kWh × 7.97p = £757.15 a year.
• Heat pump: heat needed ÷ SPF = electricity used. At SPF 2.78, 8,075 ÷ 2.78 = 2,905 kWh. Then 2,905 kWh × 26.32p = £764.51 a year.

This is the usual rule (watts × hours ÷ 1,000 = kWh; kWh × price = cost), starting from the heat your home needs, because heat pumps don't run at a fixed wattage.

You can still turn a yearly figure into an average draw. 2,905 kWh ÷ 8,760 hours in a year = 0.332 kW, or about 332 W around the clock. Real draw is far higher in winter and lower in summer. To check your own case, divide your heat pump's yearly kWh by 8,760, multiply by 1,000, and put that in as the watts.

The break-even efficiency

At the Oct–Dec 2026 cap, electricity costs 26.32 ÷ 7.97 = 3.30 times as much as gas per kWh. A heat pump breaks even when its SPF equals that price ratio multiplied by your boiler's real efficiency.

These are calculations from Ofgem's rates, not a published figure. You can redo them for your own tariff: (your electricity price ÷ your gas price) × your boiler efficiency. This version ignores standing charges, so it applies while you keep a gas supply.

The ratio moves whenever the cap changes. In the previous quarter (1 July to 30 September 2026), electricity was 26.11p and gas 7.33p, a ratio of 3.56 (Ofgem). Against an 85% boiler, the break-even then was about 3.03. Gas rose about 8.7% this quarter, which brought it down to 2.81.

That is also why figures differ between sources. The Energy Saving Trust's guide says electricity costs "around four times" as much as gas (Energy Saving Trust). That reflects prices from an earlier period; at the Oct–Dec 2026 cap the ratio works out at 3.30.

Cost by home size, and what dropping gas saves

The gas standing charge is 29.68p a day under the Oct–Dec 2026 cap. That is 29.68p × 365 = £108.33 a year (Ofgem). You only save it if you disconnect gas completely, which the Energy Saving Trust links to switching to an electric cooker (Energy Saving Trust).

The electricity standing charge (54.83p a day, or £200.13 a year) is paid either way, so it doesn't change the comparison.

Here is how the break-even works once gas is disconnected, for the medium home:

• Gas boiler total: £757.15 + £108.33 = £865.48 a year.
• Electricity that buys: £865.48 ÷ 26.32p = 3,288 kWh.
• SPF needed: 8,075 kWh of heat ÷ 3,288 kWh = 2.46.

So a median heat pump at £764.51 is about £101 a year cheaper than a new boiler once gas is gone. The same working gives the last column below. Ofgem's typical values give a low, medium and high gas user (Ofgem consultation); all rows use an 85% boiler and the Oct–Dec 2026 cap.

While you keep gas, the break-even stays at 2.81 for every size of home. The standing charge is a fixed amount, so it lowers the bar most in smaller homes.

Forecast SCOP vs measured SPF

SCOP is the seasonal efficiency your installer forecasts at design stage. SPF is what the system actually achieves over a year in your home. For the break-even sums, SPF is the number that counts.

An analysis of Ofgem metering data from 1,431 air source installs (2017 to 2022) found a median forecast SCOP of 3.59 but a measured median SPF of 2.69 (rb&m for DESNZ, RECC and GSHPA). In the medium home, that is the difference between £592 and £790 a year. Installs from 2022 alone did a little better: a median SPF of 2.74 against a forecast of 3.67. In the full set, 38% had an SPF below 2.5 and about 30% reached 3.0 or more.

The government-funded Electrification of Heat (EoH) trial found the same gap. In 91.9% of homes, the heat pump unit's measured performance was below its design SCOP, with the median 17.9% lower (Energy Systems Catapult for DESNZ). The report found little link between a system's SCOP and how well it actually performed.

The EoH trial monitored 742 homes from November 2020 to September 2023. Its median air source heat pump reached an SPF of 2.78, measured across the whole heating system including pumps and any immersion or backup heater. The middle half of homes ranged from 2.55 to 3.05, which is why those rows appear in the first table. The report says performance varies widely between installs, while differences by house type and age were not statistically significant.

Cold weather matters too. Median air source efficiency (COP) was 3.37 at 10°C outside, 2.37 at -3°C and 2.30 at -5°C, so your coldest weeks cost the most per unit of heat.

Ground source heat pumps did better in the Ofgem data: a median SPF of 3.26 against a forecast of 3.93, with 67% reaching 3.0 or more (rb&m). Hybrid systems, where a heat pump works alongside a boiler, had a lower heat-pump median of 2.50 in the EoH trial.

Your boiler matters as much as the heat pump

The Energy Saving Trust says replacing an older boiler with a heat pump makes heating cheaper to run, but against a newer gas or oil boiler a heat pump "won't necessarily be cheaper" (Energy Saving Trust).

Against an older boiler at 75%, the medium home pays £858 for gas. A median heat pump at £765 saves about £94 a year before standing charges, or about £202 if you also drop the gas standing charge.

Against a new boiler, it's closer. Since April 2018, new gas boilers fitted in existing homes in England must have an ErP efficiency of at least 92% (BEIS, Boiler Plus). But Which? warns that an A-rated boiler "isn't a surefire way to 90%+ efficiency in reality", partly because many ship with an 80°C flow temperature (Which?). A 2009 Energy Saving Trust field trial, as reported by The Heating Hub, found A-rated boilers performing mostly at the equivalent of 75–85% in real homes. That trial is old, so treat it as a rough guide.

That is why 85% is the main case here. If your boiler genuinely reaches 92%, gas costs £700 a year and a heat pump would need an SPF above 3.04 to beat it while you keep gas.

Heat pump tariffs change the picture

Everything above uses the flat price cap rate. The Energy Saving Trust analysed measured data from 546 homes and about 1.1 million combinations of technology and tariff. It found most heat pumps on a standard flat-rate tariff cost the same as or more than an efficient gas boiler to run (Energy Saving Trust).

Heat pumps on dedicated heat pump tariffs or dynamic (half-hourly) tariffs had "significantly better running costs". The right tariff could save up to £330 a year on heating bills, though the EST says its savings are scenario-based.

Heat pump tariffs are separate products, not part of the capped standard tariff. On capped multi-rate tariffs such as Economy 7, Ofgem allows a cheaper off-peak rate as long as the two rates together stay within the cap (Ofgem). To check any tariff, work out your average electricity price on it and put it into the break-even formula above.

Installation cost and grants

The Energy Saving Trust puts a typical air source heat pump at around £12,000 to install (Energy Saving Trust). In England and Wales, the Boiler Upgrade Scheme gives £7,500 towards an air or ground source heat pump, and runs until 30 December 2029 (GOV.UK). The heat pump must be fitted by an MCS-certified installer (Energy Saving Trust).

This is not financial advice. For a decision this size, get quotes from several qualified installers.

How to cut the cost

• Keep the flow temperature low. Across all heat pumps in the EoH trial, median COP was 3.50 at a 35°C flow temperature, 2.38 at 55°C and 2.02 above 65°C (EoH report). Ask installers what flow temperature and SPF they expect, not just the SCOP.
• Ask about the refrigerant. Units using R32 or R290 both had a median SPF of 2.86 in the trial, against 2.66 for older R410a units.
• Staying on gas? Turn the boiler flow down. Which? says many boilers ship at 80°C, while modern condensing combis can run at 60–65°C or lower (Which?). The Heating Hub puts the gain from weather compensation controls at 3% and load compensation at 4% (The Heating Hub).

FAQ

How much does a heat pump cost a month in the UK?

The medium-home figure of £765 a year is about £64 a month on average at the Oct–Dec 2026 cap (£764.51 ÷ 12). Real bills are much higher in winter and lower in summer, and there is no official month-by-month split.

Will these numbers change?

Yes. Ofgem sets the cap each quarter, and the electricity-to-gas price ratio drives the break-even point. Re-run the formula when new rates are published.

Is a ground source heat pump cheaper to run?

On the measured data, yes. A median SPF of 3.26 gives £652 a year for the medium home, below a new gas boiler at 85% on a flat tariff.

Sources

1. Energy price cap unit rates and standing charges – Ofgem
2. Review of typical domestic consumption values consultation – Ofgem
3. Gas and electricity prices during the 'energy crisis' and beyond – House of Commons Library
4. Heat pumps: how they work, costs and savings – Energy Saving Trust
5. We looked at over a million heat pump, technology and tariff combinations. Here's what really cuts energy bills – Energy Saving Trust
6. Electrification of Heat Demonstration Project Summary Report – Energy Systems Catapult
7. In-Situ Heat Pump Performance Analysis of Ofgem Data 2017–2022 – rb&m
8. HEAT IN BUILDINGS – Boiler Plus (final policy and consultation response) – BEIS
9. Boiler energy efficiency explained – Which?
10. Are we being misled over boiler efficiencies? – The Heating Hub
11. Boiler Upgrade Scheme – GOV.UK Find a grant
12. Boiler Upgrade Scheme explained – Energy Saving Trust

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