Gas boiler vs heat pump. The honest 2026 maths.
A gas boiler costs less upfront. A heat pump costs less over 15 years. Here is the head-to-head, the year a heat pump pulls ahead, and the suitability checklist most sites skip.
£11,450 over 10 yr
Lower upfront, plus a replacement around year 12 to 15.
£12,400 over 10 yr
Higher upfront. Pulls ahead by year 12 thanks to lower running cost and longer life.
Head-to-head
| Metric | Gas boiler | Air-source HP | Ground-source HP |
|---|---|---|---|
| Install cost (typical) | £2,500 | £12,000 | £20,000 |
| BUS grant (2026) | n/a | £7,500 | £7,500 |
| Net install cost | £2,500 | £4,500 | £12,500 |
| Annual running cost (3-bed semi) | £795 | £640 | £560 |
| Annual service cost | £100 | £150 | £170 |
| Typical lifespan | 12 to 15 yr | 20 to 25 yr | 25+ yr |
| 10-year total cost of ownership | £11,450 | £12,400 | £19,800 |
| 15-year total cost of ownership | £18,425 | £16,350 | £23,450 |
Based on indicative quotes for a typical 3-bed semi, including the Q2 2026 Ofgem cap and the 2026 BUS grant of £7,500. Real installs vary with insulation, fabric and system size.
The crossover year
Cumulative cost over 15 years for a typical 3-bed semi.
| Point in time | Cumulative gas cost | Cumulative HP cost | Notes |
|---|---|---|---|
| Year 0 | £2,500 | £4,500 | Install. Heat pump higher even after grant. |
| Year 5 | £6,975 | £8,450 | Gas still ahead. Lower install never recovered. |
| Year 10 | £11,450 | £12,400 | Heat pump within £1,000. Crossover approaching. |
| Year 12 | £15,840 | £13,980 | Gas boiler hits replacement age, adds £2,500. Heat pump now ahead. |
| Year 15 | £18,425 | £16,350 | Heat pump £2,075 ahead, still has 5 to 10 years of life left. |
Property suitability
Heat pump is right for you if
- EPC C or above, or you can reach C with insulation
- Outdoor space for a fridge-sized unit on a south or east-facing wall
- Underfloor heating, oversized rads, or you are willing to upgrade
- Mains electricity supply has the headroom for a 16A heat pump load
- You are staying in the home for at least 12 to 15 years
Stick with gas if
- EPC D, E or worse with no insulation budget
- Mid-terrace with no garden access or thin walls
- Standard 600 mm panel rads only, with no upgrade plan
- Selling within 3 to 5 years
- You need replacement now and your boiler has died
BUS grant in 2026
The Boiler Upgrade Scheme pays £7,500 toward an air-source or ground-source heat pump installation. From April 2026, a new £2,500 grant covers air-to-air heat pumps for the first time. The grant is paid by Ofgem direct to your MCS-registered installer, who discounts your invoice. There is no homeowner cashflow cost.
- Eligibility: property in England or Wales, valid EPC, no funding from another scheme for the same install.
- Requirement: installer must be MCS-certified and apply on your behalf.
- Timing: application takes 1 to 2 weeks. Grant funds reserved before installation begins.
Full grant guidance on the grants and finance page.
Hybrid systems
A heat pump for the bulk of the heating load, a gas boiler for hot water and the coldest snaps. Hybrid kits cost £4,000 to £8,000 installed. They cut gas use by 60 to 80% without requiring radiator upgrades or full electrification. Worth considering if you cannot reach EPC C with insulation alone.
What about hydrogen?
The UK government decision on hydrogen for domestic heating is expected in 2026. Our view: do not delay a boiler purchase waiting for hydrogen. Most major brands now sell hydrogen-ready models at no real price premium. If hydrogen blending happens, your boiler can be converted by a Gas Safe engineer in a single visit. See the 2035 ban page for the full policy picture.
FAQ
Is a heat pump cheaper to run than gas?
Per useful kWh, yes. A modern air-source heat pump runs at a coefficient of performance (COP) of 3 to 3.5 in real UK conditions. At the Q2 2026 caps that means about 7p per useful kWh of heat from a heat pump versus about 6.2p from a 92% efficient gas boiler. The heat pump edges it, especially on a heat-pump-friendly tariff. Annual savings on a 3-bed semi: £150 to £250.How much does a heat pump cost after the grant?
The Boiler Upgrade Scheme grant is £7,500 for an air-source or ground-source heat pump in 2026, paid direct to your MCS-registered installer. A typical ASHP installation of £10,000 to £15,000 falls to £2,500 to £7,500 net. A GSHP at £18,000 to £35,000 falls to £10,500 to £27,500 net.Can I keep my radiators with a heat pump?
Sometimes. Heat pumps run cooler water than a gas boiler (typically 45 to 50°C versus 65 to 75°C), so each radiator delivers less heat. If you have oversized radiators already (common in older homes), you may keep them. Most homes need at least some radiators upsized: typical cost £80 to £150 per radiator including labour. Underfloor heating is the gold standard.What is a hybrid heating system?
A gas boiler and a heat pump working together, with intelligent controls deciding which to use moment by moment. The heat pump handles steady-state demand. The gas boiler kicks in for hot water and very cold days. Hybrid installations cost £4,000 to £8,000. They make sense when full electrification is impractical but you want to cut gas use by 60 to 80%.