The Short Answer
At the 1 October to 31 December 2026 price cap, a heat pump running at SCOP 3.5 delivers heat at 7.5p per kWh against 8.9p from a 90% efficient gas boiler. That's the reverse of the position a year ago, and it happened because gas went up 8.7% while electricity went up 0.8% and lost its VAT. Break-even is a SCOP of 2.97, so the technology wins and a badly designed installation still loses. With the £7,500 grant the two cost about the same to fit, and over fifteen years the heat pump comes out roughly £3,600 ahead, mostly because the boiler needs replacing inside that window.
Heat Pump vs Gas Boiler: Full Comparison for UK Homeowners in 2026
Both will heat your home. They differ on what they cost to fit, what they cost to run, how long they last and what happens to those numbers when the price cap moves. Everything below is worked from the current cap rather than from last year's, which matters more than usual this time, because the October 2026 cap flipped the running-cost answer.
Upfront Costs: Heat Pump vs Gas Boiler
Typical installed cost for a 3-bed semi-detached home
Comparable to a new boiler
Heat pump cost includes hot water cylinder and any radiator upgrades needed
That chart is a three-bed semi, which is the home this whole guide is built around. Across all property types the range is wider: £9,000 to £13,000 before the grant and £1,500 to £5,500 after it, because a one-bed flat and a five-bed period house are not the same job. The Energy Saving Trust's typical figure is around £12,000. See our heat pump costs guide for the breakdown by property size.
Side-by-Side Comparison
| Factor | Air Source Heat Pump | Gas Boiler |
|---|---|---|
| Upfront cost, 3-bed semi (installed) | £9,000 – £13,000 (before grant) £1,500 – £5,500 (after £7,500 BUS grant) |
~£2,750 (typically £2,500 – £3,000) |
| Annual running cost (3-bed semi) | £790 – £1,130 at SCOP 3.5, electricity 26.32p/kWh |
£930 – £1,330 at 90% efficiency, gas 7.97p/kWh |
| Cost per kWh of heat delivered | 7.5p at SCOP 3.5 (8.8p at SCOP 3.0, 10.5p at SCOP 2.5) | 8.9p at 90% efficiency |
| Efficiency | 250–400% (SCOP 2.5–4.0). A competent install lands at 3.5; MCS will certify down to 2.8 | 89–94% (condensing) |
| Expected lifespan | 20–25 years | 10–15 years |
| Annual maintenance cost | ~£150 | ~£100 |
| Carbon emissions | Much lower, and falling every year as the grid decarbonises | Fixed by the chemistry of burning methane, so it doesn't improve |
| Requires hot water cylinder | Yes (most homes) | No (combi boiler) |
| Planning permission | Usually not required (permitted development) | Not required |
| Government grant available | Yes: £7,500 BUS | No |
| VAT rate | 0% until 31 March 2027, then 5% | 20%. The 5% reduced rate only applies to grant-funded installs for qualifying households (VAT Notice 708/6, section 3) |
| Future-proof | Yes, low carbon technology | Effectively ruled out of new English builds from 24 March 2027 by the Future Homes and Buildings Standards (no explicit ban; the 2035 existing-home ban was scrapped) |
| Comfort and heat distribution | Consistent, gentle background warmth | Fast response, high-temperature radiators |
15-Year Total Cost of Ownership
Most comparisons you'll read run over ten years and then charge the gas column for a boiler replacement in "year 12 to 15". That's a free hit: the replacement falls outside the window it's being added to. Take it out and the ten-year gap shrinks to a few hundred pounds.
Fifteen years is the honest window. It's long enough that the boiler you buy today genuinely needs replacing inside it (10 to 15 years is the usual life), and short enough that the heat pump is still running. Here it is for a three-bed semi with a heat demand of 12,000 kWh a year, at the 1 October to 31 December 2026 cap, with the £7,500 grant taken:
| Cost element | Air source heat pump | Gas boiler |
|---|---|---|
| Installation, net of the £7,500 grant | £3,500 £11,000 install, mid of the £9,000 – £13,000 band |
£2,750 typical new combi, fitted |
| Fuel, 15 years | £13,500 £900/yr: 12,000 ÷ 3.5 × 26.32p |
£15,900 £1,060/yr: 12,000 ÷ 0.9 × 7.97p |
| Annual service, 15 years | £2,250 £150/yr |
£1,500 £100/yr |
| Replacement inside the window | £0 20 to 25 year life, so it's still going |
£2,750 one replacement, around year 13 |
| 15-year total | £19,300 | £22,900 |
That's £3,600 over fifteen years, about £240 a year. Note where it comes from: £2,400 of it is the fuel, £2,750 is the boiler you don't have to replace, and the heat pump hands back £750 in higher servicing and £750 in the higher net install cost. It is not a dramatic number, and anyone quoting you a five-figure saving is making it up.
Three things that move this a long way
- No grant, and gas wins. At the full £11,000 install cost the heat pump's fifteen-year total is £26,800, which is £3,900 worse than the boiler. The £7,500 is doing the heavy lifting, not the running cost.
- A poor install, and gas wins. At SCOP 2.5 the fuel bill is £1,263 a year instead of £900, so the heat pump total climbs to £24,700 and the boiler beats it by £1,800. Break-even is a SCOP of 2.97. Get the predicted SCOP in writing.
- A heat pump tariff, and the gap roughly doubles. A blended 20p/kWh (realistic on Cosy Octopus if most of the work happens in the cheap windows) takes the fuel bill to about £686 a year, £10,290 over fifteen years, and the total to £16,000. That's £6,900 better than gas.
One thing the table leaves out in gas's favour: if the heat pump lets you cut the gas supply off entirely, you stop paying the gas standing charge of 29.68p a day, which is another £1,625 over fifteen years. Plenty of households keep the gas on for a hob, so it isn't automatic, but it's real money if you go all-electric.
Want to run these numbers for your own home? Try our heat pump vs boiler calculator. Enter your gas bill, house size, SCOP, tariff and solar setup to see your 15-year total and break-even year using the current Ofgem price cap.
The Gas Boiler Ban: What's Actually Happening in 2026
The headlines have shifted a lot in the last couple of years, so here's the current state of play:
- New-build homes (England): The Future Homes and Buildings Standards apply from 24 March 2027, under the Building Regulations etc. (Amendment) (England) Regulations 2026 (SI 2026/335). Worth being precise here, because "gas boilers banned" is a headline rather than what the law says: the regulations never mention boilers, gas or heat pumps. What they do is rewrite Part L so it covers greenhouse gas emissions, and add a brand new requirement (L3) that every new dwelling has an on-site renewable electricity system. A gas boiler can't realistically get a new home through that, which is why in practice new English homes will be built with heat pumps, heat networks or direct electric heating. There are also transitional arrangements, so homes already through building control carry on under the old rules for a while yet.
- New-build homes (Scotland): Already banned since April 2024 under the New Build Heat Standard. Scotland is running ahead of England here.
- Existing homes: The previously proposed 2035 ban on new gas boiler installs was scrapped in January 2025. The Warm Homes Plan replaces it with grants and incentives, and its stated target is to "expand the market for heat pumps to over 450,000 installations a year by 2030". There is no ban on installing a gas boiler in an existing home, and none proposed. You can keep your existing boiler indefinitely and still buy a new one if yours fails.
What this means in practice: nobody is going to rip out your working boiler, and you'll still be able to buy a gas boiler for the foreseeable future. But the grants (BUS £7,500, funded to 2030 with £2.7bn under the Warm Homes Plan) and VAT treatment (0% on heat pumps until 31 March 2027) will continue to tilt the economics toward heat pumps, and there's ongoing policy work on rebalancing electricity levies onto gas.
For homeowners whose boilers are already 8–12 years old, planning a proactive switch now, while grants are at their current level and installers are competitive, still makes sound financial sense. You're not being forced, but the incentives favour acting sooner rather than later.
When a Gas Boiler Still Makes Sense
Despite the long-term case for heat pumps, there are situations where replacing like-for-like with a gas boiler remains a reasonable choice:
- Emergency replacement: If your boiler breaks down in January and you need heating within days, a heat pump installation (typically 6 to 12 weeks from decision to running, once you've had a heat loss survey, gathered quotes and waited on the BUS voucher) is not practical. A new gas boiler can often be installed within 24–48 hours.
- You are not eligible for the BUS grant: Without the £7,500 grant, the financial case for a heat pump weakens considerably. If you're not eligible for BUS at all, because you already have a heat pump, the property is a new build, or you're replacing a renewable system, a boiler may be the only option.
- Very poorly insulated home with no budget for improvements: A heat pump in a leaky, poorly insulated home will have a lower COP and higher running costs. If you cannot address the insulation, a heat pump will be less effective than in a well-insulated property.
- You plan to move within 2–3 years: The upfront cost of a heat pump is harder to recoup over a very short occupancy period, even with the grant.
- Listed building or conservation area constraints: Some properties face planning restrictions that make outdoor unit siting difficult or impossible.
Comfort and Heating Style: An Important Difference
Heat pumps and gas boilers heat homes in different ways, and some homeowners notice the difference in comfort:
- Gas boilers fire up quickly, heat radiators to high temperatures (70–80°C), and can raise room temperatures rapidly. Many people like this responsive, on-demand heating style.
- Heat pumps run at lower flow temperatures (45–55°C) for longer periods. The heating is gentler and more consistent, maintaining a steady background temperature rather than heating up and cooling down repeatedly. Most people find this comfortable, particularly when combined with underfloor heating, but it is a different experience from a traditional boiler system.
Modern heat pump controls with weather compensation learn your home's heat loss pattern and maintain an even temperature extremely efficiently. The key is resisting the urge to turn the thermostat up and down frequently, which reduces efficiency.
The Verdict
If you can get the £7,500 grant and your installer will commit to a SCOP of 3.5 in writing, take the heat pump. It's cheaper to run at the current cap, it lasts longer, and over fifteen years it's about £3,600 ahead. That's a real number but it's not a life-changing one, so treat the carbon and the policy direction as part of the reason rather than an afterthought.
If either of those two conditions fails, think again. Without the grant, gas wins by roughly £3,900 over fifteen years. With a SCOP under 2.97, gas wins on running cost from day one, and no amount of grant money fixes a system that's been designed to run at 55°C into undersized radiators. The variable that decides this is the quality of the installation, not the technology.
For detailed cost figures, see our heat pump costs UK guide. For a step-by-step guide to claiming the £7,500 grant, see our heat pump grants guide. To understand how air source heat pumps work in practice, read our air source heat pump guide.
