How much does a new boiler cost in the UK?
Updated 19 October 2026 · Reviewed by Steve Wolfe
Replacing a combi boiler with a new one in the same place typically costs £2,500 to £4,500 in the UK, with fitting, a filter and controls. Switching from a system or regular boiler with a hot water cylinder to a combi costs about £3,500 to £6,000. The boiler itself is often only around half the bill.
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Typical costs
Typical UK prices for a three-bed house, supplied and fitted by a Gas Safe registered engineer with the old boiler taken away.
| Type | Typical cost |
|---|---|
| Combi to combi, same place £2,500–£4,500 The simplest swap, reusing the pipework and flue route. On site: usually a day | £2,500–£4,500 |
| System or regular boiler to combi £3,500–£6,000 The hot water cylinder and loft tanks taken out, and the pipework changed. | £3,500–£6,000 |
| Air source heat pump, before the grant £11,000–£15,500 For comparison. The £7,500 Boiler Upgrade Scheme grant comes off this in England and Wales. | £11,000–£15,500 |
Our reading of the published guides and official figures listed under Sources, rounded. Moving the boiler, a new flue route or new radiators cost more.
What's in the price
The boiler is often only around half the bill. Checkatrade puts a typical gas combi at about £1,500 for the boiler and £1,000 to £2,000 to fit it. A full quote usually also covers:
- Taking out and disposing of the old boiler.
- A new flue, and changes to the gas pipe or condensate drain if needed.
- Cleaning the system, either a chemical flush or a power flush, which Which? puts at about £300 to £750.
- A magnetic filter to catch sludge, about £60 to £160 plus £50 to £150 to fit (Checkatrade).
- Controls, such as a smart or programmable thermostat, from about £150.
- Registering the installation and the manufacturer's warranty.
What changes the price
- The kind of swap. Combi to combi in the same place is the cheapest. Switching from a system or regular boiler means taking out the hot water cylinder and loft tanks and changing pipework, which Checkatrade averages at about £4,000.
- Moving the boiler. A new position means new gas, water and condensate pipes and a new flue.
- The boiler itself. Budget, mid-range and premium brands vary by a few hundred to over a thousand pounds, and longer warranties usually cost more.
- The size of the house. Bigger homes, and homes with more than one bathroom, may need a bigger combi or a system boiler with a cylinder.
- The state of the system. Sludgy radiators, old valves or a failing pump add to the job.
New boiler or heat pump?
Official figures from the Boiler Upgrade Scheme put the typical installed cost of an air source heat pump at about £12,900 between April and June 2026, with most between about £11,100 and £15,600. The £7,500 grant in England and Wales brings a typical one down to about £5,400, roughly the cost of a system-to-combi conversion. Whether it's cheaper to run depends on your insulation, radiator sizes and electricity tariff, so ask for a heat loss survey before deciding.
Before you get quotes
- Note what you have now: the boiler type and age, where it is, and how many radiators and bathrooms you have.
- Decide whether it's staying in the same place.
- Check every quote is from a Gas Safe registered engineer (or OFTEC for oil), and names the boiler model and warranty.
- Ask whether a system clean, filter, controls and taking away the old boiler are included.
- Get two or three quotes. Prices for the same boiler vary a lot between installers.
An example Ballpark
What Ballpark gave for this job on 16 October 2026. It’s an example we worked out, not a customer’s price.
Replace an old combi boiler with a new combi in the same place, in a three-bed house in Birmingham with ten radiators.
-
Budget like-for-like £1,900–£2,750
Supply and fit of an entry-level 24 to 28 kW combi in the same place, basic flue and controls, and removal of the old boiler.
-
Mid-range combi swapClosest to the job £2,500–£3,500
Supply and fit of a good-quality combi from a major brand in the same place, smart thermostat, magnetic filter, system flush and removal of the old boiler.
-
Premium with extras £3,500–£4,750
Premium combi with a longer warranty, smart controls, magnetic filter, power flush of the ten radiators and new thermostatic radiator valves.
Based on
- Boiler stays in the same position
- Existing pipework and flue route are reusable
- Gas Safe fitter, prices include VAT
- No radiator replacements
What a trade will ask you
Have answers ready and your quotes (and your ballpark) will be closer to the real price.
- What have you got now? A combi, a system boiler with a cylinder, or a regular boiler with tanks in the loft?
- Is the boiler staying in the same place?
- How many bedrooms, bathrooms and radiators?
- Is it gas, oil, LPG or electric?
- Is the old boiler still working, or has it broken down?
- Do you want smart controls, a filter or a power flush?
Common questions
How much does it cost to replace a combi boiler?
Usually £2,500 to £4,500 for a like-for-like swap in the same place, fitted. Checkatrade puts a gas combi at about £650 to £3,000 for the boiler and £1,000 to £2,000 to fit, with an average of about £3,000 in total.
How long does it take to fit a new boiler?
A straight combi swap usually takes a day, and Checkatrade puts a simple installation at 4 to 6 hours. Changing from a system or regular boiler to a combi, or moving the boiler, takes longer.
Should I get a heat pump instead?
It's worth considering, especially if your boiler is old and your house is reasonably well insulated. Official figures put the typical installed cost of an air source heat pump at about £12,900, and the £7,500 Boiler Upgrade Scheme grant in England and Wales brings that down to around £5,400. Running costs depend on your insulation, radiators and electricity tariff, so get a proper heat loss survey.
Can I get a grant for a new boiler?
Not usually for a like-for-like gas boiler. The main government grant is the Boiler Upgrade Scheme, which gives £7,500 towards a heat pump, or £5,000 towards a biomass boiler, in England and Wales. There's an extra £1,500 until March 2027 for heat pumps in homes heated by oil or LPG with no mains gas.
Who can fit a new boiler?
Gas boilers must be fitted by a Gas Safe registered engineer, and oil boilers by an OFTEC registered technician. They register the installation, and you should get a certificate and the manufacturer's warranty registered in your name.
Are boiler prices going up?
Yes. Official figures from the Department for Business and Trade show central heating boiler prices up 5.7% in the year to August 2026.
What would yours cost?
Describe your new boiler and get a ballpark for your house in a couple of minutes. Free, and you don’t have to get quotes.
Get my ballparkSources
- Checkatrade, new boiler cost (Oct 2026). Boiler and fitting costs, like-for-like and conversion prices, timescales and extras
- GOV.UK, Boiler Upgrade Scheme. Grant amounts and conditions
- Department for Energy Security and Net Zero, Boiler Upgrade Scheme statistics, August 2026 (Sep 2026). Installed cost of air source heat pumps, April to June 2026
- Department for Business and Trade, building materials and components statistics, September 2026 (Oct 2026). Central heating boiler price index, year to August 2026
- Which?, boiler prices (Sep 2025). Extra cost of switching to a combi, and power flush prices