Comparison · Heating
Heat pump vs gas boiler in 2026: which costs less for a UK home?
TL;DR
- Out-of-pocket install: heat pump often LESS than gas boiler after BUS grant.
- Running costs are similar on standard tariffs; heat-pump tariffs widen the gap.
- Heat pumps last 15–20 years vs 10–15 for boilers.
- Heat pump emissions are roughly one-quarter of gas boiler emissions.
- Gas boiler wins only on instant install + tolerance of leaky old homes.
| Air-source heat pump | Modern gas boiler | |
|---|---|---|
| Install cost (pre-grant) | £8,000–£14,000 | £2,500–£4,500 |
| BUS grant | −£7,500 (E&W) | — |
| Net upfront cost | £1,500–£6,500 | £2,500–£4,500 |
| Annual running cost | £900–£1,400 | £1,000–£1,500 |
| Heating-only carbon | ~0.4–0.8 t CO₂/yr | ~2.2 t CO₂/yr |
| Expected lifespan | 15–20 years | 10–15 years |
| Servicing cost | £100–£180/yr | £90–£150/yr |
| Flow temperature | 45–55°C | 70–80°C |
| Radiator upgrade needed? | Often, 1–4 rooms | No |
| Hot water cylinder | Yes (~£1,500) | Combi: no; system: yes |
| Install time | 2–3 days | 1 day |
| Permitted development? | Yes (most homes) | Yes |
Upfront cost — heat pump often beats a new boiler in 2026
The headline shift: the Boiler Upgrade Scheme (BUS) pays a flat £7,500 toward an air-source heat pump install in England and Wales. That deduction makes the heat pump out-of-pocket cost LOWER than a new gas boiler for most UK semi-detached homes — a reversal from the pre-2023 economics. The boiler is cheaper to physically install but not to BUY after the grant is netted off.
Pre-grant heat-pump cost runs £8,000–£14,000 for a 5–10 kW unit with cylinder + 1–4 radiator upgrades. A typical UK 3-bed semi lands in the middle of that range — call it £10,500. After BUS deduction the homeowner pays £3,000. A new combi gas boiler in the same property costs £2,500–£3,500 installed by an A-rated engineer. The maths now favours the heat pump on day one, before any running-cost difference.
Running cost reality — closer than you’d think
On equivalent tariffs (standard variable), a heat pump and a modern condensing gas boiler in a typical UK semi run within £100–£200 of each other for heat. The heat pump uses about 3,400 kWh of electricity (SCOP 3.5); the boiler uses about 13,000 kWh of gas. At 2026 prices that’s roughly £600 of electricity vs £800 of gas, plus standing charges. The boiler edges ahead on per-kWh fuel cost; the heat pump claws it back on conversion efficiency.
Heat-pump-specific tariffs (Octopus Cosy, British Gas Heat Pump Plus, EDF GoElectric) widen the gap further — they price electricity at 13–18p per kWh during heat-pump windows vs 25–35p on standard tariffs. On those tariffs the heat pump comes in £200–£400 cheaper than a boiler for the same heat demand. The savings compound across the 15–20-year unit lifespan.
The carbon angle
A UK home heating with gas emits about 2.2 tonnes of CO₂ per year. The same home on a heat pump emits 0.4–0.8 tonnes — roughly one-quarter, driven by the UK grid’s declining carbon intensity (~150 g/kWh in 2026 vs 200 g/kWh in 2022). That gap widens every year as the grid decarbonises further; a gas boiler installed today locks in those 2.2 tonnes for the next 10–15 years.
When a gas boiler still wins (rare in 2026)
Two scenarios where a new gas boiler remains the right call:
- Emergency replacement.Your boiler died in January; you need heat by Friday. A heat-pump install takes 2–10 weeks from quote to commissioning. A boiler swap takes a day. Some installers in 2026 will lend you a portable electric heater while a heat-pump install proceeds, but most won’t.
- Severely uninsulated property. A 1900s solid-wall terrace with single-glazing and no loft insulation will struggle to maintain comfort on heat-pump flow temperatures. The fabric retrofit needs to happen first, then the heat pump can size sensibly. In 2026 the BUS grant explicitly requires loft + cavity insulation recommendations on the EPC to be cleared.
Resale and futureproofing
UK estate agents now flag low-carbon heating as a sale accelerant for properties marketed above £400,000. A heat pump install adds £5,000–£15,000 to the EPC’s indicative running-cost saving over the certificate’s 10-year window, which lifts the energy band visibly (D to C is common). The 2025 ban on new gas boiler installs in new builds, plus the Future Homes Standard, has shifted buyer expectation: a 2035-onward boiler purchase is a known depreciating-asset decision.
Switching pathway — what to do this week
- Run a free pre-survey at propertoasty.com/check to get the BUS-eligibility verdict for your specific property + an installer-ready report.
- Send the report to 2–3 MCS-certified installers covering your area. Compare heat-loss calculation numbers (W/m²) — if two installers’ numbers differ by more than 20%, ask why.
- Lock in a quote before any radiator decisions. Most installers absorb radiator swaps within the BUS-grant scope.
The takeaway
For most UK homeowners with the option, the 2026 numbers favour an air-source heat pump over a new gas boiler — lower out-of-pocket cost after BUS, similar or better running cost, longer lifespan, and dramatically lower carbon. The exceptions (emergency replacement, severely uninsulated properties) are real but increasingly narrow.
Related reading
- Heat pump vs gas running costs UK 2026: the real numbers — worked annual cost figures by house size, tariff, and insulation level.
- Heat pump payback period UK 2026 — gas-replacement, oil-replacement, LPG-replacement scenarios with BUS factored in.
- BUS grant application walkthrough — how the £7,500 actually flows from Ofgem to your invoice.
- Fabric-first retrofit before a heat pump — clearing the loft + cavity recommendations that gate the grant.
Sources
- GOV.UK — Boiler Upgrade Scheme — accessed May 2026
- Ofgem — Boiler Upgrade Scheme guidance — accessed May 2026
- Energy Saving Trust — Air source heat pumps — accessed May 2026
- MCS — Find an installer — accessed May 2026
- GOV.UK — Domestic energy prices (BEIS quarterly data) — accessed May 2026