This article contains affiliate links. We may earn a commission if you buy through our links, at no extra cost to you. Heat-pump prices are from Heatable and iHeat’s heat-pump pages and Ofgem, checked 26 August 2026, and the boiler band is from our new boiler cost page. Figures change from time to time, so the live quote is what counts. Last reviewed: August 2026.
Heat pump versus boiler in 2026 is a grant question as much as a kit question. A new combi is still the cheaper, faster swap. But an air source heat pump, after the £7,500 Boiler Upgrade Scheme grant (£9,000 if you’re off-gas replacing oil or LPG), can land in the same thousands as a boiler once the survey is done. Running costs then come down to your tariff, insulation and flow temperature, not a slogan.
If you already know you’re staying on gas, skip to the boiler box lower down. If a heat pump is even a maybe, the money is in our air source heat pump cost guide, and the boiler side in our new boiler cost guide.
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The short version
Fit a heat pump if you’re in England or Wales, the house can take a survey, and you can wait weeks rather than a day. After the grant, iHeat’s live packages sit at £3,095 to £4,495 before extras, and Heatable’s typical band is roughly £0 to £5,500. Fit a new combi if the boiler has died, you’ve no cylinder space, the house is a poor candidate, or you’re outside the grant area. Either way, quote Heatable then iHeat, on the heat-pump links first if a heat pump is even a maybe.
What you actually pay
A replacement combi is a like-for-like swap: new boiler, flue, filter, a day on site. Our new boiler cost band is £2,000 to £4,500 fitted for a typical UK job, and there’s no grant on a gas boiler. An air source heat pump is a designed job: outdoor unit, often a cylinder if you have a combi, sometimes larger radiators and electrics, then the grant off the invoice. Heatable put a typical install at £7,000 to £13,000 before the grant; iHeat publish three fixed air-to-water packages.
| Option | Sticker | Grant | What you pay |
|---|---|---|---|
| New combi (typical) | £2,000–£4,500 | None | £2,000–£4,500 |
| Heatable typical ASHP | £7,000–£13,000 | £7,500 | About £0–£5,500 |
| iHeat Alpha Hydro | £10,595 inc VAT | £7,500 | £3,095 |
| iHeat Vaillant aroTHERM Plus | £11,495 inc VAT | £7,500 | £3,995 |
| iHeat Worcester 5800i | £11,995 inc VAT | £7,500 | £4,495 |
The after-grant column is list minus the £7,500 England and Wales air-to-water grant; off-gas oil or LPG can be £9,000 to 31 March 2027, and survey extras sit on top. On sticker the heat pump is clearly more. After the grant, a clean air-source job can sit right next to a mid-range combi. That’s the 2026 maths, and it collapses if the survey adds a cylinder, a consumer unit and a stack of radiators, or if you’re in Scotland or Northern Ireland where the grant doesn’t apply.
Running costs: heat pump vs gas boiler
A well-designed air source heat pump in a decent house can run at around 300% efficiency, in Heatable’s words, or up to about four times a gas boiler on iHeat’s. That’s a design result, not a promise on every Victorian terrace. iHeat put typical bill savings against gas at £200 to £600 a year, with a “£500+” figure used as marketing on the same page. Your tariff, insulation and flow temperature decide the real number.
Heat pumps run on electricity, and gas is still cheaper per kWh than standard-rate electricity, which is exactly why a poorly designed heat pump on old radiators can cost more to run than the combi it replaced. The survey exists to stop that. Pairing with solar is a separate quote, and Heatable sell both, but don’t buy a heat pump to “beat gas this winter” without a survey. The grant closes the install gap; running costs only fall if the house is a genuine fit.
When a new combi still wins
A new gas boiler is still the job if any of these are true:
- The boiler is dead and you need heat this week. A combi is a day on site; a heat pump is a survey, a design and 2 to 5 days, booked weeks out. iHeat’s next-day heat-pump claim still sits behind a survey.
- You have a combi and no space for a cylinder. Heatable are blunt that a regular boiler with a tank is more straightforward; a combi needs somewhere to put a cylinder.
- The house is a poor candidate. Old, leaky, tired radiators. Significant upgrades may be needed first, and the grant isn’t a magic wand for the fabric.
- You’re outside England and Wales. The grant is England and Wales only; Scotland and Northern Ireland run different schemes.
- You’re moving soon. A like-for-like combi is easier to explain to a buyer who just wants hot water than a designed heat-pump system.
Time on site, and what changes in the house
| New combi | Air source heat pump | |
|---|---|---|
| Survey | Usually a short booking call | Heat-loss survey (Heatable £240, deducted if they install) |
| On site | Typically a day | Heatable 2–5 days; iHeat FAQ 2–3 days |
| Lead time | Often next-day on boiler pages | Heatable 2–4 weeks after survey; iHeat next-day is a booking claim |
| Hot water | Combi, no tank | Cylinder if you currently have a combi |
| Grant | None | £7,500 / £9,000 off-gas oil or LPG |
For the full job, see heat pump installation, and for who to use, heat pump installers.
Heatable first, iHeat for a named model or 0%
Both are MCS-certified and both apply for the £7,500 grant, so you compare on the balance after it comes off. Heatable is the first quote for most homes; iHeat is the second number, or the first if you already want Vaillant aroTHERM Plus, Alpha Hydro or Worcester 5800i. If you’ve decided on a boiler instead, use the boiler box above.
- Instant estimate, then a £240 heat-loss survey
- £240 refunded if they install
- BUS paperwork handled, MCS + Which?
- Monthly instalments on heat pumps
- Alpha Hydro, Vaillant aroTHERM Plus or Worcester 5800i
- Fixed price, 7-year warranty
- 0% APR, no deposit
- BUS paperwork handled, MCS engineers
The grant that tilts heat pump vs boiler
The grant is installer-led: an MCS fitter submits the voucher, Ofgem asks you to confirm consent, and the money comes off the invoice. Ofgem’s property-owner page currently pays:
- £7,500 for air-to-water and ground source heat pumps.
- £2,500 for air-to-air, which isn’t a wet-heating swap.
- £9,000 for air-to-water or ground source in eligible off-gas properties replacing oil or LPG, from 21 July 2026 until 31 March 2027.
It’s England and Wales only, and hybrids that keep a fossil-fuel boiler alongside a heat pump aren’t eligible. Heatable and iHeat both handle the paperwork. Full rules are in our Boiler Upgrade Scheme guide.
How to decide
- House looks a fit and you can wait: quote Heatable then iHeat on heat pumps, and compare the after-grant prices.
- Named model (Vaillant, Alpha, Worcester): iHeat first on the heat-pump link, Heatable second.
- Off-gas on oil or LPG: ask both to price the £9,000 uplift.
- Boiler dead this week, no cylinder space, or outside the grant: stay on gas, use the boiler box above and our best combi boiler UK guide.
Frequently asked questions: heat pump vs boiler
Is a heat pump cheaper than a new boiler in 2026?
Before the grant, no. After the £7,500 grant, a clean air-source job can sit in the same thousands as a mid-range combi, iHeat’s Alpha Hydro is £3,095 after £7,500 if the survey adds nothing. A typical new combi is still £2,000 to £4,500 with no grant.
Will a heat pump cut my bills versus gas?
Only if the design is right. iHeat quote £200 to £600 a year against gas on their FAQ, with “£500+” used as marketing on the same page, and Heatable cite around 300% efficiency in a well-insulated home. A leaky house on standard-rate electricity can go the other way.
Can I keep my combi and add a heat pump?
A hybrid that keeps a fossil-fuel boiler alongside a heat pump isn’t eligible for the Boiler Upgrade Scheme. If you want the grant, the heat pump replaces the boiler.
Is there a grant for a new gas boiler?
No. The Boiler Upgrade Scheme is for heat pumps, and biomass in limited rural cases, not a gas combi. A new boiler is the cheaper job up front, but it comes with no grant.
How long does each job take?
A combi is typically a day. A heat pump is 2 to 5 days on site for Heatable, booked 2 to 4 weeks after the survey, or 2 to 3 days on iHeat’s air-source FAQ. Don’t copy boiler next-day timing onto a heat pump.
Who should I quote?
For a heat pump, Heatable first via the heat-pump link, then iHeat. If you’re staying on gas, use Heatable then iHeat on the boiler links in the box above. Installer detail is in our Heatable review and iHeat review.