1. Home
  2. Costs
  3. New boiler cost calculator

New boiler cost calculator

Work out what a new gas boiler costs, fitted, in your part of the UK. Pick a combi, system or regular boiler and say whether it's a straight swap, a move or a conversion. You get a low to high range and a typical price, with each part of the job listed.

Fitter connecting copper pipes beneath a new white combi boiler on a kitchen wall

System and regular prices assume the cylinder or tanks are already there and stay.

Cleans out sludge. Often recommended on older systems.

Your result

Estimated cost

£1,800 – £4,000

A combi boiler fitted by a Gas Safe engineer.

Typical cost
£2,800
Boiler and parts
£1,200 – £2,000typical £1,800. Our split of the supply-and-fit price.
Fitting labour
£600 – £2,000typical £1,000
  • Prices are estimates from published UK cost guides (checked 2026-11-06). Get at least three quotes.
  • The Boiler Upgrade Scheme (£7,500 grant, £9,000 for oil or LPG homes with no mains gas until 31 March 2027) is for heat pumps. It does not cover a gas boiler.
  • Check whether each quote includes VAT. The 0% VAT rate on energy-saving items (until 31 March 2027) covers things like heat pumps, solar panels and insulation. We have not found it applying to gas boilers.

Got a quote already? See how it compares with typical UK prices.

Check a quote

How to use the new boiler cost calculator

  1. Under What are you doing?, choose a straight swap, a swap with the boiler moved to a new spot, or a conversion of a regular or system boiler to a combi.
  2. Pick the New boiler type: combi, system or regular. This box is hidden for a conversion, because the new boiler is always a combi.
  3. Switch on Powerflush the heating system and Smart thermostat if you want them priced in.
  4. Choose Where do you live? Labour is adjusted for your area. The boiler itself is not.
  5. Read the range and the typical price, then tap Add to shopping list to keep it, or Share link to send it to your installer.

Why use this calculator

It splits the price into the boiler and the fitting. That's why moving to London changes the labour but not the cost of the boiler, and you can see which lines are doing the work.

It prices the jobs people actually ask about: a straight swap, moving the boiler, converting to a combi, a powerflush and a smart thermostat. Most guides give one 'from' price.

It shows its working. Under How we worked it out you can see every step with your own choices, so you can check it against a quote.

It's clear about grants. The Boiler Upgrade Scheme is for heat pumps, not gas boilers, and the page says so.

How we worked it out

Your numbers, step by step. This updates as you change the calculator.

  1. A new combi boiler fitted in the same place costs about £1,800 to £4,000 (typical £2,800), supply and fit.
  2. We split that into the boiler and parts (£1,200 to £2,000) and the fitting labour (£600 to £2,000), using the labour-only guide price.
  3. Prices are for the UK average, so no regional adjustment.
  4. Add it up: low £1,800, typical £2,800, high £4,000.

How we estimate the cost

We start with the published price of a boiler supplied and fitted in the same place: combi £1,800 to £4,000 (typical £2,800), system £2,500 to £4,500 (typical £3,200), regular £2,300 to £4,500 (typical £3,000). The typical figure is our midpoint of the commonly quoted prices. It is not a published average.

We then split that price in two. Fitting labour comes from the labour-only guide price, £600 to £2,000 (typical £1,000). The rest is the boiler and parts. For a combi that leaves £1,200 to £2,000 (typical £1,800). That split is our own.

Then we add what you chose:

  • Moving the boiler: £400 to £1,000 (typical £750) for extra pipework and a new flue.
  • Converting to a combi: the whole job costs about £2,500 to £4,500 (typical £4,000). We use that total instead of the straight-swap price.
  • Powerflush: £450 to £1,000 (typical £700).
  • Smart thermostat: £150 to £300 (typical £200).

We add up all the lows, all the typicals and all the highs to give the range.

What’s included

  • The boiler, the parts and the fitting, by a Gas Safe registered engineer.
  • For a conversion, removing the old tanks and cylinder and the extra pipework.
  • For system and regular boilers, the price assumes your cylinder and tanks already exist and stay in place.
  • Not included: a new cylinder, a new flue where you haven’t chosen to move the boiler, new radiators, and VAT if a quote adds it.

What changes the price

  • The type of boiler. A combi is usually the cheapest to swap. System and regular boilers cost a little more.
  • The job. Moving the boiler or converting it takes more time and pipework.
  • Your area. Only the labour parts (fitting, moving the boiler, powerflush) move with region. We use London ×1.25, South East ×1.15, Scotland ×0.93, Wales ×0.92, the North ×0.92 and Northern Ireland ×0.88. The boiler itself costs about the same everywhere, so a London combi swap comes out around 9% higher overall, not 25%.
  • Extras. A powerflush and a smart thermostat are priced separately.
  • The quote itself. Sources for the same job can be hundreds of pounds apart, which is why we show a range.

Tips

  • Get at least three quotes from Gas Safe registered engineers, and ask each one what's included: flue, controls, filter, old boiler removal and the guarantee.
  • Ask whether the quote includes a powerflush. Older systems with sludge in them often need one, and it's easy to be quoted for it as an extra.
  • Moving a boiler or converting to a combi adds pipework and sometimes a new flue. Ask for these as separate lines so you can compare quotes fairly.
  • A system or regular boiler price assumes your hot water cylinder and loft tanks are in good order. A new cylinder costs extra.
  • Got a quote already? Put it through the quote checker to see how it compares.
  • Thinking about a heat pump instead? Try the heat pump cost calculator to see the price after the grant.

FAQs

How much does a new boiler cost in the UK?
A new combi boiler swapped like for like costs about £1,800 to £4,000 fitted, with a typical price of £2,800. A system boiler is about £2,500 to £4,500 (typical £3,200) and a regular boiler about £2,300 to £4,500 (typical £3,000). Published guides disagree a lot, so get quotes.
How much does a new combi boiler cost fitted?
About £1,800 to £4,000 for a straight swap in the same place, typically £2,800. That's the boiler, parts and fitting. Add about £450 to £1,000 for a powerflush and about £150 to £300 for a smart thermostat if you want them.
How much does it cost to replace a boiler in a 3 bed house?
The prices we use depend on the boiler type and the job, not the number of bedrooms. In our figures a like-for-like combi swap is about £1,800 to £4,000 whatever the house size, though a bigger home may need a bigger boiler. Ask your installer to check the boiler is the right size for your home.
How much does it cost to convert a regular boiler to a combi?
About £2,500 to £4,500 in total, typically £4,000. That covers removing the tanks and cylinder and doing extra pipework, which usually takes around three days. We found only two sources for this, so treat the range as rough.
Can I get a grant for a new boiler?
Not for a gas boiler. The Boiler Upgrade Scheme gives £7,500 off an air source heat pump (£9,000 for oil or LPG homes with no mains gas, until 31 March 2027), but it does not cover gas boilers. Check the current rules on GOV.UK.
Is VAT charged on a new boiler installation?
Check each quote, because some include VAT and some don't. The 0% rate for energy-saving items runs until 31 March 2027 and covers things like heat pumps, solar panels and insulation, but we have not found it applying to gas boilers. HMRC treats controls fitted as part of a new boiler job as part of one standard-rated supply.
Do I need a Gas Safe engineer to fit a new boiler?
Yes, you should use a Gas Safe registered engineer for any gas boiler work. Ask to see their Gas Safe ID card, and check them on the Gas Safe Register. They can tell you what paperwork you'll get after the job.

Last reviewed: 6 November 2026 · How we calculate · Report an error