Quick Answer
Gas boilers cost £2,000–£4,000 to install and are cheaper upfront. Heat pumps cost £10,000–£20,000 but attract a £7,500 government grant (BUS), run on electricity, and produce lower carbon emissions. Heat pumps make financial sense in well-insulated homes — gas boilers remain the practical choice for most UK homes in 2026.
The heat pump vs gas boiler debate is one of the most important home decisions for UK homeowners in 2026. With rising gas prices, the government's Boiler Upgrade Scheme, and growing pressure to decarbonise home heating, more people are seriously considering making the switch. This guide gives you an honest, numbers-based comparison so you can make the right choice for your home.
In this guide
How Each System Works
Gas Boiler
A gas boiler burns natural gas to heat water, which then circulates through your radiators and hot water cylinder. Modern condensing gas boilers are highly efficient (90–94% efficiency), easy to install, and familiar to most UK heating engineers. They provide rapid heat-up and can easily cope with the coldest UK winters.
Heat Pump
A heat pump doesn't generate heat by burning fuel — instead, it extracts heat energy from the outside air (air source) or ground (ground source) and transfers it inside, using a refrigerant cycle. For every 1 unit of electricity used, a heat pump typically delivers 2.5–4 units of heat — making it 250–400% efficient. Heat pumps run on electricity, which can be generated from renewable sources.
Heat pumps work at lower flow temperatures (typically 40–55°C) compared to gas boilers (65–80°C), meaning they work best with underfloor heating or large, properly sized radiators. In a draughty, poorly insulated home, they struggle to maintain comfortable temperatures efficiently.
Full Cost Comparison
| Factor | Gas Boiler | Air Source Heat Pump |
|---|---|---|
| Installation cost | £2,000 – £4,000 | £10,000 – £20,000 |
| After BUS grant (£7,500) | N/A | Effectively £3,000 – £12,500 |
| Typical running cost/yr (3-bed home) | £1,000 – £1,500 | £800 – £1,300 (well insulated) |
| Lifespan | 10–15 years | 20–25 years |
| Annual service cost | £80 – £150 | £150 – £300 |
| Carbon footprint | High (gas combustion) | Low (if on green tariff) |
| Installation time | 1 day | 2–3 days |
| Radiator upgrades needed? | No | Often yes (larger radiators) |
| Works in poorly insulated homes? | Yes | Poor performance |
| Hot water included? | Yes (combi or cylinder) | Yes (with cylinder) |
For full breakdown of heat pump installation costs, including what's included and how to apply for the grant, read our dedicated guide on how much it costs to install a heat pump in the UK. For gas boiler costs, see how much a new boiler costs.
Running Costs: The Real Numbers
Running costs depend on energy prices, which fluctuate. As of 2026, electricity costs roughly three times as much per unit as gas in the UK. However, heat pumps use electricity far more efficiently than gas boilers use gas — so the bill comparison is closer than it might appear.
In a well-insulated 3-bedroom home, a modern gas boiler might use around 12,000–15,000 kWh of gas per year. At roughly 7p/kWh, that's £840–£1,050/year. An equivalent heat pump running at a Coefficient of Performance (COP) of 3 would use around 4,000–5,000 kWh of electricity. At roughly 24p/kWh, that's £960–£1,200/year — broadly comparable, with carbon emissions one-third of the gas equivalent.
In a poorly insulated home, the heat pump's COP drops — it works harder for the same output — and running costs can exceed gas. This is why insulation upgrades often go hand-in-hand with heat pump installations.
The Boiler Upgrade Scheme (BUS) Grant
The UK government's Boiler Upgrade Scheme provides a grant of £7,500 towards an air source or ground source heat pump. The grant is applied directly by your MCS-certified installer — you don't claim it separately. This significantly changes the financial case for heat pumps, making an air source heat pump effectively £3,000–£12,500 after the grant.
To qualify for BUS, your home must: be in England or Wales, have a valid EPC (Energy Performance Certificate), not have been recommended for cavity wall or loft insulation (or have already had it done), and use an MCS-certified installer. Read our complete guide to the Boiler Upgrade Scheme for full eligibility details.
When a Heat Pump Makes Sense
A heat pump is the right choice when:
- Your home has good insulation (EPC rating C or above) — loft, cavity wall, and ideally floor insulation
- You have or are willing to install underfloor heating or oversized radiators
- You want to reduce your carbon footprint significantly, particularly if on a green electricity tariff
- You're planning to stay in the home long-term and can benefit from the 20–25 year lifespan
- Your existing boiler needs replacing anyway — the net cost difference narrows
- You qualify for the £7,500 BUS grant
When a Gas Boiler Is the Better Choice
A gas boiler makes more practical sense when:
- Your home has poor insulation and you can't afford or access improvements right now
- Your property is rented — the investment timeline doesn't work for landlords
- You have a flat or small home where heat pump outdoor unit installation isn't feasible
- Your budget is limited — a new gas boiler at £2,000–£4,000 is far more accessible
- Your current boiler has 5+ years left and you want to plan your heat pump transition properly
For help choosing the right gas boiler type for your home, see our guide on how to choose the right boiler. And when you're ready to hire, ensure you use a Gas Safe registered engineer — our guide on what to look for in a Gas Safe engineer covers what to check.
Frequently Asked Questions
Will gas boilers be banned in the UK?+
The UK government has signalled that new gas boiler installations in new-build homes will be phased out, though the timeline has shifted several times. As of 2026, there is no ban on replacing like-for-like gas boilers in existing homes. The current direction is towards heat pumps for new builds, with existing homes transitioning over time rather than by a hard deadline.
Do heat pumps work in cold UK winters?+
Modern air source heat pumps are rated to work efficiently down to -15°C to -20°C. UK winters, even in Scotland, rarely exceed -10°C for sustained periods. Cold-climate heat pumps from brands like Mitsubishi, Daikin, and Vaillant are well proven in Scandinavian and Alpine conditions. Efficiency does drop in very cold weather, but they continue to provide heat.
Can a heat pump heat my home as quickly as a gas boiler?+
No — heat pumps heat more slowly and steadily. They work best running at a lower, consistent temperature rather than being turned on and off for rapid warm-up. This means longer heating periods (often continuous low-level heating) rather than the short blasts UK homeowners are used to with gas. Smart controls manage this automatically.
Is underfloor heating necessary for a heat pump?+
Not strictly, but it is ideal. Heat pumps can work with radiators, but the radiators may need to be 1.5–2x the size of those used with a gas boiler to deliver sufficient warmth at lower flow temperatures. A heat pump engineer will assess your existing radiators and advise whether upgrades are needed.
How noisy is an air source heat pump?+
Modern heat pumps produce around 45–55 dB when operating — similar to a refrigerator or quiet conversation. They run almost continuously at low speed rather than intermittently at high speed, which most homeowners find unobtrusive. Siting the unit away from bedrooms and living rooms helps. There are permitted development rules on installation location.
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