The short answer
Boiler or heat pump comes down to your house more than the technology, and a heat pump vs gas boiler comparison usually settles quickly. If your house is draughty, your budget is tight or you need heating back this week, a new gas boiler is usually the right call. If your home is reasonably well insulated, you plan to stay ten years or more and you can claim a grant, a heat pump is worth serious comparison. Most homes fall clearly on one side once you answer the seven questions below. Neither system is the right answer for every house, so be wary of anyone who recommends the same one to everybody.
Boiler and heat pump side by side
Prices are typical UK figures, checked October 2026. Your installer will give you a fixed price for your home.
| Compare | New gas boiler | Air source heat pump |
|---|---|---|
| Typical fitted price | £2,200 to £3,400 (combi swap) | £11,000 to £14,500 before any grant |
| After grants | No national boiler grant for most homes | £3,500 to £7,000 in England and Wales after the £7,500 grant |
| Fitting time | Usually 1 day | 2 to 5 days |
| Hot water | On demand from a combi, no cylinder needed | Stored in a cylinder, which needs a cupboard |
| Radiators | Your existing ones usually work | Some may need upsizing, £300 to £600 each |
| Works best in | Almost any home on the gas grid | Homes with sensible insulation and space outside for the unit |
| Lifespan | Around 10 to 15 years | Similar or longer, with annual servicing |
| Installer must be | Gas Safe registered | MCS certified (needed to claim the grant) |
What kind of house is it?
Semis, detached houses and bungalows with space for an outdoor unit tend to suit heat pumps. Mid-terraces can work, but finding a spot for the unit that keeps it clear of windows and neighbours takes more thought. Flats and tenements are the hardest: limited outdoor space, shared walls and building rules often rule a heat pump out, and a combi is usually the practical answer.
How well does it hold heat?
Insulation affects a heat pump more than anything else on this list. A heat pump runs at a lower flow temperature (the temperature of the water sent to your radiators) than a boiler, so it heats the house gently and steadily rather than in quick bursts. That works well in a home that keeps its heat and poorly in one that leaks it.
Good signs: a full loft of insulation, filled cavity walls, double glazing and no obvious draughts. Warning signs: solid walls with no insulation, single glazing or rooms that go cold within an hour of the heating going off. An MCS installer will do a room-by-room heat loss survey before quoting, and you should insist on one.
Are you on the gas grid?
If you are on mains gas, a new boiler is the cheaper upfront option and you can compare it directly with a heat pump. If you are off the grid and heating with oil or LPG, the case for a heat pump is stronger, because those fuels are often dearer and an oil boiler needs a tank and deliveries. Oil boilers are fitted by OFTEC-registered technicians, and replacing oil with a heat pump still qualifies for the grant in England and Wales.
What can you afford?
A combi swap at £2,200 to £3,400 is the cheapest way to get reliable heating back. A heat pump, even after the £7,500 grant, usually costs £3,500 to £7,000 in England and Wales, plus any radiator upgrades. If spending that now would be a stretch, a new boiler is a reasonable choice that gives you about a decade to plan the next move.
Which grants can you get?
Grant rules differ across the UK. Check the current rules before you sign anything.
| Nation | What is available (October 2026) |
|---|---|
| England | Boiler Upgrade Scheme: £7,500 off an air source or ground source heat pump, claimed by your MCS-certified installer. You need a valid EPC and must be replacing fossil-fuel heating. |
| Wales | The same Boiler Upgrade Scheme as England. |
| Scotland | Home Energy Scotland grant, with an optional interest-free loan. You must apply before any work starts. See homeenergyscotland.org. |
| Northern Ireland | The Boiler Upgrade Scheme does not apply. Check NI Energy Advice for any current support, and do not budget on a grant until it is confirmed. |
Full details for England and Wales are on gov.uk.
How long will you stay?
A heat pump costs more upfront and saves money slowly, if it saves money at all in your home. If you expect to move within three to five years, you may not stay long enough to see the benefit. If this is your home for the next decade or more, the longer view favours a heat pump in a house that suits one.
How do you use hot water?
A combi heats water as you use it, so it never runs out but it struggles when two showers run at once. A heat pump stores hot water in a cylinder, which handles several taps at once but needs a cupboard about the size of a wardrobe and can run out after a long run of baths. A household of five with two bathrooms may prefer stored hot water anyway. A couple in a flat with no spare cupboard almost certainly will not.
Putting it together
- Mostly warning signs on insulation, space and budget: get a new boiler and see the boiler replacement prices.
- A well-insulated house, outdoor space, a grant and a long stay ahead: compare heat pump installation properly.
- A mix of both: ask for a straight verdict on your home before you get any quote.
Not sure which side you are on? Tell us about your home on the quote form. We will give you our honest recommendation and connect you with one certified local installer for a fixed price.
Common questions
Is a heat pump cheaper to run than a gas boiler?
It can be, but it depends on the house and your electricity tariff. A heat pump in a well-insulated home, running at a low flow temperature on a suitable tariff, often costs less to run than an old gas boiler. In a draughty house with small radiators, running costs can match or exceed a new combi.
Will a heat pump work in an older house?
Many older homes run heat pumps well, as long as heat loss is brought under control first. Loft insulation, cavity wall insulation where possible and a few larger radiators make the difference. Solid-walled houses that cannot be insulated are harder, and an MCS installer's heat loss survey will tell you which side of the line you are on.
Do I need perfect insulation to get the Boiler Upgrade Scheme grant?
No. In England and Wales the £7,500 grant (as of October 2026) has no insulation requirement, but you need a valid EPC and you must be replacing fossil-fuel heating. Your MCS-certified installer applies for it and takes it off your bill. Check the current rules before you commit, because schemes can change.
Can I fit a new boiler now and switch to a heat pump later?
Yes, and for many households that is the sensible route. A new combi lasts 10 to 15 years, which gives you time to insulate, save and watch how grants and tariffs develop. Ask your installer to fit radiators and pipework that would suit a heat pump if you are replacing them anyway.
What if my home suits neither system very well?
Then we will say so. Some homes need insulation or a radiator upgrade before any new system makes sense, and you should hear that before anyone quotes you for a new system. Tell us about your home and we will give you the verdict first.