A like-for-like combi boiler swap in the UK typically costs about £2,000 to £4,000 installed, with a median around £2,300 reported in 2026. Converting a regular or system boiler to a combi costs about £3,000 to £5,700, and a full new heating system costs more.
If you are thinking about a heat pump instead, the Boiler Upgrade Scheme currently takes £7,500 off an air-to-water system. See our heat pump guide.
Boiler and central heating cost estimator
The estimator uses indicative prices from the sources below and does not replace a quote. The full central heating range is an indicative allowance for a three-bed home, because published guides give little detail on it, so get itemised quotes.
Boiler cost by type of job
A like-for-like swap is the cheapest. Moving the boiler, changing type or fitting new pipework costs more.
| Job | Typical cost |
|---|---|
| Combi boiler swap, like for like | About £2,000 to £4,000 (reported median about £2,300) |
| Regular or system boiler swap, like for like | About £2,500 to £4,500 |
| Change regular or system boiler to a combi | About £3,000 to £5,700 |
| New boiler and full central heating system | About £5,000 to £8,500 for a three-bed home |
Budget combi boilers can be fitted for about £1,800 to £2,500, and premium makes cost more. Published guides range from £1,500 to £4,500 for a combi swap.
Typical boiler cost at a glance
Typical installed range by type of job.
What pushes the cost up or down
- Boiler type and brand: combi, system and regular boilers all differ in price, and premium brands cost more.
- Output: larger homes need higher output boilers.
- Changing type: moving from a regular boiler to a combi means new pipework and removing the tanks.
- Flue and location: moving the boiler or changing the flue adds labour.
- System condition: sludge and old radiators can mean a powerflush or new radiators.
- Installer: prices from large firms, local engineers and online installers can differ.
Costs people forget
| Item | Typical allowance |
|---|---|
| Powerflush and filter | £400 to £900, protects the new boiler |
| Smart controls | £150 to £350 |
| New radiators or valves | Often needed in older systems |
| New hot water cylinder | £900 to £2,200 if you change type |
| Making good and decoration | Pipework and flue changes can leave damage |
| Contingency | 5 to 10 percent |
Boilers must be installed by a Gas Safe registered engineer, and the installer should notify building control through a competent person scheme. See our Gas Safe engineer, heating engineer and combi boiler pages.
Boiler or heat pump?
A new gas boiler costs less upfront, but a heat pump can qualify for the Boiler Upgrade Scheme grant of £7,500 on air-to-water systems in England and Wales.
See the Boiler Upgrade Scheme and our heat pump guide to compare costs.
Gas Safe, building regulations and warranties
Only a Gas Safe registered engineer can legally install or service a gas boiler. Ask to see their ID card, and check the register online. The installer must meet the building regulations, including controls and efficiency requirements, and notify building control or use a competent person scheme. You should get a Benchmark commissioning record and the manufacturer's warranty details.
Cutting the cost without cutting corners
- Get at least three itemised quotes and compare boiler make, output and warranty, not only the total.
- Keep the boiler where it is to avoid flue and pipework costs.
- Install a magnetic filter and consider a powerflush so the new boiler lasts.
- Replace the boiler in summer, when installers are quieter.
- Look at heat pumps if you want to cut carbon, and check the grants available.
Sources and further reading
- Heatable: how much do new boilers cost Quote data for combi replacement in 2026
- Screwfix: how much is a new boiler Merchant price guide
- MyJobQuote: boiler installation cost Installation cost ranges
- GOV.UK: Apply for the Boiler Upgrade Scheme Heat pump grant details
External links open in a new tab. Costs combine several published price guides, which differ. Last checked November 2026.
Frequently asked questions
How much does a new boiler cost in the UK?
A like-for-like combi swap typically costs about 2,000 to 4,000 pounds installed, with a median of around 2,300 pounds reported in 2026. Changing boiler type or fitting a full system costs more.
How much does it cost to install a combi boiler?
About 2,000 to 4,000 pounds like for like, or 3,000 to 5,700 pounds when converting from a regular or system boiler.
How long does it take to fit a new boiler?
A like-for-like swap often takes a day or two. Changing boiler type or fitting a new system takes several days.
Is a new boiler worth it?
An old, inefficient boiler can cost more to run and break down. A modern condensing boiler with good controls can save on bills, though savings depend on your home.
Can I get a grant for a new boiler?
There is no general grant for gas boilers. The Boiler Upgrade Scheme offers 7,500 pounds towards an air-to-water heat pump in England and Wales. Check gov.uk for current terms.