How much does a boiler replacement cost in the UK in 2026?

A like-for-like combi boiler swap in the UK typically costs in the region of £1,500–£3,000 including installation in 2026. Converting from a conventional system to a combi usually runs higher, at around £2,500–£4,500, and a full new installation with a hot water cylinder can reach £3,000–£5,500. Where your job lands in those ranges depends on the boiler brand, your home's size, pipework condition and where you live.

Those are market-wide figures, not quotes. The only way to know what your boiler replacement will cost is to have Gas Safe registered engineers look at your specific job — which is why comparing several quotes matters so much.

What drives the price up or down

Two identical boilers can be installed for very different prices. The main factors installers price in:

• Boiler type and brand — premium brands with longer warranties cost more upfront.
• Relocating the boiler — moving it to another room adds pipework and labour.
• System changes — switching from a conventional system to a combi means removing tanks and re-routing pipes.
• Flue and condensate runs — awkward flue positions or long condensate pipes add time.
• Extras — magnetic filters, power flushing, smart thermostats and radiator work are often quoted alongside.
• Where you live — labour rates vary by region, and hard-water areas like Essex often benefit from a filter or scale reducer.

Combi, system or conventional: which are you paying for?

A combi boiler heats water on demand and needs no tanks or cylinder, which keeps installation simpler and usually cheaper. A system boiler feeds a hot water cylinder — a better fit for homes with multiple bathrooms. A conventional (heat-only) boiler with loft tanks suits some older heating systems, and replacing like-for-like avoids re-engineering the whole system.

If your current setup works for your household, a like-for-like swap is normally the most cost-effective option. If your needs have changed — more bathrooms, a loft conversion, poor water pressure — it can be worth paying for a system change while the installer is already there.

How to compare boiler quotes properly

Price alone doesn't tell you much. When you compare quotes, check each one covers the same scope:

• The exact boiler model and warranty length, in writing.
• Whether a system flush, magnetic filter and thermostat are included.
• Who registers the installation with Gas Safe and handles the building-regulations notification.
• Whether old equipment removal and disposal is included.
• Labour guarantee on the installation itself, separate from the boiler warranty.

Getting quotes without the ring-around

On Ace Services you post your boiler job once, free, and up to three vetted Gas Safe registered engineers quote you directly. Your phone number stays private until you choose who to hire, so you can compare prices, brands and warranties without a single cold call. Tradespeople pay nothing to quote — just a small success fee if you hire them — so quotes aren't inflated to cover lead fees.