Mains gas boiler to air source heat pump
Typical annual saving: £100–£400. Estimated payback: 10–14 years (with grant).
| Heat pump | New gas boiler | |
|---|---|---|
| Install (after grant) | £500–£8,500 | £2,500–£4,500 |
| Lifespan | 20+ years | 10–15 years |
| Annual running (semi) | £900–£1,400 | £1,000–£1,500 |
| Carbon (10 yrs) | ~3 tCO₂e | ~22 tCO₂e |
Free, no-obligation
Compare for my home
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What kind of property is it?
Editorial standards
- Independent — No Installer Sponsorship
- Both Sides Compared, No Pre-Decided Winner
- Numbers Sourced From Ofgem + ESCT 2024–25 Studies
- Filterable By Property Type & Current Heating
- Includes BUS Grant + Real Tariff Data
- Reviewed By An MCS-Qualified Heat Engineer
Comparison is intentionally honest — for some homes a high-efficiency boiler genuinely is the better choice. HeatPumpVsBoiler.co.uk has no commercial bias toward either option.
Switching from mains gas boiler: what changes
Switching from a gas boiler to a heat pump is the UK's most common heat pump scenario — but also the one with the narrowest savings. Gas is cheap relative to electricity, so payback depends heavily on insulation level and the electricity tariff. Octopus Cosy and similar heat-pump-friendly tariffs can shift the maths significantly.
The £7,500 BUS grant brings the heat pump install cost in line with — sometimes below — a like-for-like new combi boiler. Where you save: 20+ year heat pump lifespan vs 10–15 year boiler, no annual gas safety check, lower long-term carbon levy exposure.
Heat pump vs gas boiler — the verdict
How they compare across 25 years
A new gas boiler typically lasts 10–15 years; a heat pump 20+. Across an average 25-year homeownership window, here is the difference for a typical UK semi-detached home.
lifetime carbon saving over a like-for-like gas boiler swap
boiler replacements avoided over a heat pump's 20-year lifespan
estimated 25-year total cost gap (heat pump cheaper, off-gas-grid)
average heat-pump efficiency vs. a 90% efficient combi boiler
How it works
Three steps to a clear answer
No obligation, no pushy follow-ups, no fees from us — ever.
Side-by-side comparison
We compare a heat pump vs a new gas boiler on five axes: install cost (after grants), annual running cost (price-cap and standing charges included), expected lifetime, comfort and noise, carbon footprint, and resale-value impact.
Filtered for your home
The right answer depends on your property. We filter for your property type, current heating, insulation level and region — comparing the options that actually apply to you, not the average UK home.
Clear next step
If a heat pump wins for your situation, we connect you with installers. If a new boiler is genuinely the better choice, we say so — no incentive to push a heat pump that won't suit your home.
Common questions
Air source heat pump FAQs
Installed costs typically run £8,000 to £14,000 before grant for a normal home. Detached or larger properties can reach £16,000. After the £7,500 BUS grant in England & Wales, most homeowners pay £500–£8,500. Scotland's Home Energy Scotland scheme offers up to £15,000 in combined grant + interest-free loan, often making the heat pump cheaper than a like-for-like boiler replacement.
Verify any installer's MCS certification at mcscertified.com.
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The £7,500 BUS grant runs to 2028 — there's no rush, but waiting another year on an old gas, oil or LPG boiler costs you running-cost savings every month. A free survey tells you whether the fit is straightforward, with zero commitment.
Educational content — not a substitute for an MCS-certified survey.
Authoritative sources cited
- Energy Saving Trust UK heat pump trial 2024 ↗750-home field trial of UK heat-pump performance — used for the SCOP, comfort, and noise figures.
- Ofgem domestic gas + electric tariff data ↗Live price-cap and standing-charge data — used to calculate running-cost comparisons.
- Gas Safe Register ↗UK official register of gas-safe boiler installers — quoted on the boiler side of every comparison.
- Climate Change Committee — UK net-zero pathway ↗Independent statutory body advising UK government on carbon. Source for the 25-year carbon-emission projections in our comparison tables.
Statistics and figures on this site are derived from these sources unless otherwise stated. Errors? We correct promptly — see our corrections policy.
Continue your research
More UK heat pump resources
Sister sites we operate, each focused on a different decision step.