Comparison · 2025/26
Gas vs Electric Heating: Every UK Option Compared
About 23 million UK households heat with gas — the dominant heating fuel since the North Sea boom of the 1970s. Roughly 4 million heat with electricity, mostly off-grid or in flats. From 2025/26 the conversation has shifted: heat pumps, backed by a £7,500 Boiler Upgrade Scheme grant, are now installed at scale; the gas-boiler ban in new builds has been delayed to 2027+ but is approaching; and Ofgem unit prices have decoupled gas (cheap) from electricity (4x as expensive per kWh). This guide compares three real options for a typical 3-bed semi: gas combi, direct electric, and air-source heat pump.
At a Glance
| Feature | Gas combi | Direct electric | Air-source heat pump |
|---|---|---|---|
| Unit fuel price (2025/26) | ≈ 6p/kWh | ≈ 25p/kWh | ≈ 25p/kWh ÷ COP 3 |
| Efficiency | 88-94% | ≈ 100% | 280-400% (SCOP 2.8-4.0) |
| Effective cost per kWh heat | ≈ 6.5p | ≈ 25p | 6.3-9p |
| Install cost (after grant) | £2,000-£3,500 | £3,000-£6,000 | £2,500-£7,500 net |
| Typical lifespan | 10-15 years | 15-25 years | 15-20 years |
| Annual maintenance | £80-£150 | £0-£50 | £150-£250 |
| Carbon per kWh heat | ≈ 200 g | ≈ 150 g | ≈ 50 g |
| Affected by 2035 ban | Yes (new installs) | No | No |
Unit Cost — The 4× Differential
The starting point for any UK heating comparison is the unit cost of fuel. Under the Ofgem default tariff cap for Q3 2025, the typical UK direct-debit customer pays roughly 6.0p per kWh for gas and 24.5p per kWh for electricity — a four-times differential. That gap is the single most important number in the comparison and the reason gas central heating remains cheapest for the great majority of UK homes.
The differential is structural, not arbitrary. Gas is taxed lightly, electricity carries policy levies (renewables obligation, capacity market, social-tariff obligations) totalling 8-10p/kWh, and historical wholesale gas has been cheap relative to electricity. The 2022 European gas crisis briefly inverted the relationship before normalising — Ofgem still expects the 4× ratio to persist into the late 2020s, although Government policy reform may rebalance levies between fuels over time.
Standing charges also matter: gas adds around 33p/day (£120/year) on top of unit consumption, electricity 60p/day (£220/year). A dual-fuel household pays around £340/year of standing charges before turning anything on — a meaningful baseline that disproportionately affects low-consumption homes (small flats, second homes, holiday lets).
Efficiency — Where Heat Pumps Win
Efficiency turns the unit-cost picture on its head for heat pumps. A modern condensing gas boiler delivers 88-94% of the gas's energy as useful heat — the rest leaves as steam in the flue. A direct electric radiator delivers near 100% of the electricity as heat. A heat pump, by contrast, delivers 280-400% — the Coefficient of Performance multiplier from moving heat rather than generating it.
The Seasonal Coefficient of Performance (SCOP) is the more useful headline number, averaging across a UK year of varying outdoor temperatures. Typical 2025/26 SCOP for air-source heat pumps is 2.8-3.5 in well-installed retrofits, 3.0-3.6 in new builds with low-temperature radiators or underfloor heating. Ground-source heat pumps reach 3.5-4.2 thanks to the more stable ground temperature.
At SCOP 3.0 a heat pump delivers heat at an effective unit cost of 25 ÷ 3 = 8.3p per kWh — still more than gas at 6p, but only by a quarter rather than 4×. At SCOP 4.0 (achievable in good ground-source installs or excellent air-source in well-insulated homes) the figure drops to 6.3p, fully competitive with gas. The headline of "electric is 4× pricier" understates the heat-pump case quite dramatically.
Install Cost and the £7,500 BUS Grant
Upfront cost is where heat pumps still struggle in 2025/26. A new gas combi boiler fully installed costs £2,000-£3,500 — a single morning of plumber work plus the boiler unit. A direct-electric system (storage heaters or panel heaters and a hot water cylinder) runs £3,000-£6,000. An air-source heat pump install runs £10,000-£15,000 gross before grant.
The Boiler Upgrade Scheme grant administered by Ofgem on behalf of DESNZ offers £7,500 toward an air-source heat pump install in England and Wales (since 2024, increased from £5,000). Ground-source heat pumps and biomass boilers receive the same £7,500. Scotland operates the Home Energy Scotland grant of up to £7,500 with an additional £7,500 interest-free loan. Northern Ireland has historically operated smaller grants under the Northern Ireland Sustainable Energy Programme.
After grant, a typical air-source heat pump retrofit nets £2,500-£7,500 — still higher than a gas boiler replacement, but the gap has narrowed materially. Ground- source heat pumps stay expensive at £18,000-£35,000 gross because of the borehole or trench drilling. The decision for most homeowners now sits between “pay £3,000 now for another 12-year gas cycle” and “pay £5,000 now for a 20-year heat-pump install”.
Winter Bills — A 3-Bed Semi
A typical UK 3-bed semi uses around 11,500 kWh of gas per year for heating and hot water under Ofgem's “medium use” profile, with about 70% consumed in October-March. Convert that to delivered heat: gas boiler at 90% efficiency delivers 10,350 kWh; an electric system at 100% would need 10,350 kWh of electricity to do the same; a heat pump at SCOP 3.0 needs 3,450 kWh of electricity.
| System | Fuel use/year | Unit price | Annual fuel cost | Standing charge | Total annual |
|---|---|---|---|---|---|
| Gas combi (90% eff) | 11,500 kWh gas | 6.0p | £690 | £120 | £810 |
| Direct electric | 10,350 kWh elec | 24.5p | £2,536 | £220 | £2,756 |
| Heat pump SCOP 3.0 | 3,450 kWh elec | 24.5p | £845 | £220 | £1,065 |
| Heat pump on Cosy Octopus (avg 18p) | 3,450 kWh elec | 18p | £621 | £220 | £841 |
Gas remains the cheapest on the standard tariff, but a heat pump on a heat-pump-optimised tariff comes within £30/year of gas — and uses much less primary energy. Direct electric is 3× the cost and only viable where gas is unavailable. The gap between gas and heat pump narrows further if you also generate solar PV in summer to offset hot water and shoulder-season heating, or if you have an EV-loading time-of-use tariff available.
The 2035 Boiler Ban — Status
UK policy on phasing out gas boilers has been on a winding path. The 2019 announcement targeted a 2025 ban on gas boilers in new-build homes. That was relaxed in 2023 to a 2035 target for new installations in existing homes, and the new-build ban delayed. The current Future Homes Standard, due to be confirmed in legislation around 2025-2026 for implementation from 2027 or later, is expected to mandate low-carbon heating in new builds — typically heat pumps with backup direct electric.
For existing homes, the 2035 phase-out target remains a non-binding policy ambition rather than a hard ban. Heat pumps are being encouraged via the BUS grant and the Clean Heat Market Mechanism (a manufacturer-level obligation that effectively levies gas boiler sales). The political landscape remains uncertain — Government changes in 2024 reset some assumptions and the regulatory pathway through 2030 is genuinely unclear.
For practical planning: a gas boiler installed in 2025 will not become illegal during its 12-15 year service life. By the time of replacement (somewhere 2037-2040 for a current install), policy will be clear and heat-pump prices will likely have fallen substantially. The strategic case for replacing a working boiler today is weak; the case for choosing a heat pump at end-of-life of an existing boiler is stronger and growing each year.
Carbon Footprint
Burning natural gas in a domestic boiler emits roughly 0.18 kg CO2 per kWh of gas, or about 200 g per kWh of useful heat after boiler efficiency loss. UK grid electricity has decarbonised dramatically — average grid intensity 2024-25 was around 0.15 kg CO2/kWh, down from 0.40 kg in 2014. That number falls further every year as renewables and nuclear replace coal and gas generation.
Direct resistive electric heating now produces roughly 150 g CO2 per kWh of delivered heat — already lower than gas. A heat pump using a third of that electricity is around 50 g CO2 per kWh of heat — about a quarter of gas. As the grid continues to decarbonise toward Net Zero 2050, the heat-pump carbon advantage grows; the gas advantage is fixed by combustion chemistry and cannot improve.
For a 3-bed semi delivering 10,350 kWh of heat per year: gas boiler emits roughly 2,070 kg CO2/year; direct electric emits 1,550 kg; heat pump emits 520 kg. Over a 15-year boiler lifetime, switching from gas to heat pump avoids around 23 tonnes of CO2 emissions — equivalent to two return flights from London to Sydney per year. The carbon argument is the strongest single reason to choose a heat pump on its merits, even setting aside fuel cost.
When Each System Makes Sense
Gas central heating: still the right answer for the great majority of UK households in 2025/26 if you have a working boiler approaching mid-life or you are not planning a major renovation. The cheapest running cost, the cheapest install, and proven technology. The carbon downside is real but not dominant if you do not plan to live in the property indefinitely.
Direct electric heating (storage heaters or panel heaters): only the right answer where gas is unavailable (off-grid rural, all-electric flats, conservation areas without gas infrastructure). It is the most expensive to run by a substantial margin and should be regarded as transitional toward heat pumps, not a long-term choice. New builds without gas connections should be specifying heat pumps under the Future Homes Standard.
Air-source heat pump: the right answer when your gas boiler is at end-of-life (12-15 years) and you have a moderately insulated home with space for an outdoor condenser unit. Eligible for £7,500 BUS grant; long lifespan; substantial carbon saving; running cost competitive with gas on optimised tariffs. Ground-source heat pumps make sense if you have garden or land for a ground loop and budget for the £18k-£35k install, mostly for new builds, country homes, and small estates.