How Much Does a New Boiler Cost in the UK?

A boiler breakdown in the middle of winter is stressful enough without the added worry of not knowing what a replacement should cost. Quotes can vary by thousands of pounds between installers, which makes it hard to tell a fair price from an inflated one. This guide breaks down what UK households typically pay for a new boiler — supply and installation together — by boiler type, and explains the extras that can quietly push a quote up. All figures are guide ranges from UK cost guides, not fixed prices, so always compare at least two or three written quotes for your own home before you commit.

The short answer: typical installed prices

For a straightforward, like-for-like replacement — the same type of boiler in the same place — most households pay somewhere in the region of £2,500 to £4,000 supplied and fitted. Checkatrade’s cost guide puts a like-for-like combi replacement at £2,500–£4,000, with an average total cost of around £3,000 for a gas boiler supplied and installed. A system boiler replacement and a conventional (regular) boiler replacement both average around £3,000 on the same basis.

Wider market ranges are broader because they capture everything from a small flat to a large, complicated installation. Uswitch, using Checkatrade prices checked in September 2026, lists combi boilers at £1,650–£6,000 including installation, and both system and conventional boilers at £2,500–£4,100. Where your quote lands within those ranges depends mainly on the size and brand of boiler you choose, and how much work your existing system needs.

Changing the type of boiler costs more than swapping like-for-like. Converting from a system or conventional boiler to a combi averages around £4,000 supplied and installed, because the cylinder and tanks have to be removed and pipework altered.

Costs broken down by boiler type

Combi boilers

A combi heats water on demand and provides your heating from a single unit, with no separate cylinder or tank. Checkatrade puts the average supply-only price of a combi at around £1,500, with gas combi units ranging from about £650 to £3,000 depending on size and brand. Installation typically adds £1,000–£2,000. That gives the like-for-like installed range of £2,500–£4,000 above, with £3,000 as a realistic average to budget for. If you are still deciding whether a combi suits your home, our guide to combi vs system vs regular boilers walks through the differences.

System boilers

A system boiler works with a separate hot water cylinder, so it can feed several taps or showers at once. The average supply-only price is again around £1,500, and a system boiler replacement averages around £3,000 supplied and installed. Bear in mind that if your existing cylinder is old and also needs replacing, that will be quoted on top of the boiler price — ask whether the cylinder is included before you compare quotes.

Regular (conventional) boilers

A regular boiler — also called conventional or heat-only — needs both a hot water cylinder and a cold water tank, usually in the loft. Supply-only prices average around £1,500, and a replacement averages around £3,000 supplied and installed. Regular boilers are most common in older homes that already have the tanks and pipework in place, where a like-for-like swap keeps the work simple.

What pushes the price up?

Several common extras explain why two quotes for “a new boiler” can look so different:

• Changing boiler type or location. Conversions average around £4,000, and moving a boiler to a new position adds pipework, flue work and labour.
• Installation labour. Expect £1,000–£2,000 for installation on top of the unit price, at the higher end for complex jobs.
• A magnetic filter. These protect the new boiler from sludge and debris. Checkatrade lists £60–£160 for supply only, plus £50–£150 to install.
• Smart or wireless controls. A Wi-Fi-enabled heating controller costs around £150, and better controls help you avoid heating an empty home.
• System cleaning. An older, sludged-up system may need flushing or cleaning before a new boiler goes in, which adds time and cost.

None of these is necessarily money wasted — a filter and decent controls protect your investment — but each should be itemised on the quote so you can see what you are paying for.

Efficiency: what a new boiler could save

All modern boilers sold in the UK must be A-rated under the ErP rating scale, which runs from A (most efficient) to G (least). New condensing boilers typically achieve ErP efficiency ratings of around 92–94%, while an old G-rated boiler may be running at less than 70% efficiency — meaning a noticeable share of the gas you pay for never becomes useful heat.

The Energy Saving Trust estimates that replacing an old G-rated boiler with a new A-rated condensing boiler, together with a programmer, room thermostat and thermostatic radiator valves, could save around £320 a year in a semi-detached house and around £500 a year in a detached house. Your own saving will depend on your current boiler, your home and how you heat it, so treat these as illustrations rather than promises.

Repair or replace?

Boilers typically last between 10 and 15 years. If yours is younger, reliable and the fault is minor, a repair is usually the cheaper route: Checkatrade puts a typical boiler repair at around £300 on average. If the boiler is well into its second decade, breaking down repeatedly, or a single repair quote runs into several hundred pounds, replacement often works out better value — especially once the efficiency gap is factored in. If your boiler has stopped working today, try the safe checks in boiler not working? 7 checks before you call an engineer before paying for a call-out.

Getting a fair quote

Ask each installer for a written, itemised quote covering the boiler make and model, installation, any extras such as filters and controls, removal of the old boiler, and the warranty length. Gas boiler installation must be carried out by a Gas Safe registered engineer — you can check an engineer’s registration on the Gas Safe Register. Finally, if you are replacing an old boiler anyway, it is worth comparing the long-term picture with a heat pump: our guide to how much a heat pump costs covers the (much higher) upfront prices and the grants that can offset them.

Conclusion

As a planning figure, budget around £3,000 for a typical like-for-like gas boiler replacement, £2,500–£4,000 for most combi swaps, and around £4,000 if you are changing boiler type. Get itemised quotes, confirm the engineer is Gas Safe registered, and make sure filters, controls and cylinder work are either clearly included or clearly excluded. A boiler is a 10–15 year purchase, so the cheapest quote is not always the best value — efficiency, warranty and a clean installation matter just as much.

Frequently Asked Questions

How much does a new combi boiler cost fitted?

A like-for-like combi replacement typically costs £2,500–£4,000 supplied and installed, with an average total of around £3,000 for a gas combi. Broader market ranges run from about £1,650 to £6,000 once larger homes, premium brands and complex installations are included.

How much is the boiler itself, before installation?

Checkatrade puts the average supply-only price at around £1,500 for combi, system and conventional gas boilers, with gas combi units ranging from roughly £650 to £3,000. Installation usually adds a further £1,000–£2,000.

How long does a new boiler last?

Typically between 10 and 15 years, provided it is serviced annually. Annual servicing is also usually a condition of keeping the manufacturer’s warranty valid.

Is it worth replacing a working but old boiler?

It can be. If your boiler is G-rated and running at less than 70% efficiency, Energy Saving Trust estimates suggest a new A-rated model with proper controls could save a few hundred pounds a year on gas, depending on your property type. Weigh that against the installed cost and how long you plan to stay in the home.