How much does a new boiler cost in the UK? (2026 guide)

A new gas boiler in the UK typically costs £1,800 to £4,500 fitted in 2026. Where you land in that range depends on the type of boiler, the brand, how much pipework has to change and how easy the installation is. This guide breaks down what you are actually paying for so a quote is easier to judge.

The headline numbers

These are supply-and-fit figures from independent Gas Safe registered engineers. National chains and “boiler on finance” providers usually sit at the top of each band or above it, because the monthly plan carries interest and a marketing overhead.

What makes up the price

The boiler unit: £600 to £1,600. A budget combi from a value brand starts around £600. A mid-range 30–35kW combi from a mainstream manufacturer is £900 to £1,200. Premium models with a 10-year warranty run £1,300 to £1,600. A bigger house that needs a system boiler and a hot water cylinder adds £300 to £600 for the cylinder if it also needs replacing.

Labour: £500 to £1,000. A like-for-like combi swap is usually a one-day job for two engineers. Moving the boiler to a different wall, converting from a conventional system, or working in an awkward loft adds a day and a few hundred pounds.

The extras that surprise people:

• A chemical flush or power flush, £150 to £500. Fitting a new boiler onto a sludged-up system voids most warranties, so a flush is often non-negotiable, not an upsell.
• A magnetic system filter, £90 to £150 fitted. Manufacturers increasingly require one for the warranty.
• A new flue or flue extension, £80 to £200 if the position changes.
• Upgrading the gas supply pipe, £120 to £400 if the existing pipe is too narrow for a modern combi.
• Condensate pipework and a drain, £60 to £150 if there is nowhere nearby for it to run.
• Making good, plastering, boxing in, tiling. Most engineers leave this to you.

Combi, system or regular: why the type drives the price

A combi heats water on demand and needs no tank or cylinder, so it is the cheapest to fit in a one-bathroom home and the most common replacement. A system boiler keeps a hot water cylinder and suits homes with two or more bathrooms or poor mains pressure; the boiler is a similar price but you may be paying for a cylinder too. A regular (conventional) boiler keeps both a cylinder and a loft tank, usually only replaced like-for-like in older or larger properties. Converting from regular to combi is the priciest route because tanks come out, pipes are capped and the hot water pipework is reworked.

How to keep the quote down

1. Get three written quotes from Gas Safe registered engineers. Prices for the same job vary by £800 or more.
2. Ask for the boiler make, model and kW output in writing. “A new combi” is not a quote.
3. Fit, don’t move. Keeping the boiler in the same place saves a day of labour.
4. Right-size it. An oversized boiler costs more to buy and run and cycles more. A competent engineer sizes on a heat-loss calculation, not a guess.
5. Book outside the October–January rush if you can. Demand and prices peak with the first cold snap.
6. Be wary of “free boiler” and long finance deals. The interest usually adds £1,000+ over the term.

Before you sign

• Confirm the engineer’s Gas Safe registration on the official register. Every registered engineer carries an ID card you can ask to see.
• Check the quote lists the flush, filter, flue and gas pipe explicitly, so there is no day-of surprise.
• Ask who registers the warranty with the manufacturer and get the paperwork.
• Get the Benchmark checklist completed and the boiler’s commissioning details filled in. You will need it for warranty claims and when you sell.

Ready to compare prices? Get free, no-obligation quotes from Gas Safe registered engineers covering your postcode, or browse the directory to see who is registered in your area.