How much does a new boiler cost in 2026? Get an instant estimate based on boiler type, property size, and whether you need a full system change or a straightforward swap.
Typical UK costs
£1,800–£6,500
Range across all configurations, before regional adjustment
Prices include supply and installation by a Gas Safe registered engineer. Like-for-like replacements are cheaper as existing pipework can be reused. Converting between boiler types adds £500-£1,000+ for pipework changes, cylinder installation or removal, and possible flue relocation. Excludes powerflush (£300-£500) or radiator upgrades.
Last updated: March 2026
Prices include supply and installation by a Gas Safe registered engineer. Like-for-like replacements are cheaper as existing pipework can be reused. Converting between boiler types adds £500-£1,000+ for pipework changes, cylinder installation or removal, and possible flue relocation. Excludes powerflush (£300-£500) or radiator upgrades.
Prices last updated: March 2026. Estimates are indicative and based on UK averages.
Replacing your boiler is one of the most common — and most dreaded — home expenses. The good news is that a like-for-like swap (same boiler type, same location) is the cheapest and quickest option, often completed in a single day.
Combi boilers are the most popular choice in the UK, accounting for around 70% of installations. They heat water on demand with no separate tank or cylinder, making them ideal for smaller homes. For larger properties (4+ bedrooms or multiple bathrooms), a system boiler with an unvented hot water cylinder delivers better water pressure and simultaneous supply.
The biggest cost variable is whether you are swapping like-for-like or converting between systems. A straightforward combi-to-combi swap typically costs £2,200–£3,800 installed. Converting from a conventional system to a combi adds £500–£1,000+ for removing the hot water cylinder, rerouting pipework, and potentially relocating the flue.
Hidden costs to watch for include a powerflush (£300–£500, recommended if your system has sludge), new thermostatic radiator valves (£15–£30 each), upgrading the gas supply pipe, and building a cupboard or boxing around a relocated boiler. Always get at least three quotes and check your installer is Gas Safe registered.
A straightforward like-for-like boiler swap typically takes one day (6–8 hours). Converting between boiler types (e.g. conventional to combi) usually takes 2–3 days due to additional pipework, cylinder removal, and possible flue relocation.
For 1–3 bedroom homes with one bathroom, a combi boiler is usually the best and cheapest option. For larger homes with multiple bathrooms, a system boiler with an unvented cylinder provides better hot water flow to multiple outlets simultaneously.
Most boilers last 10–15 years. If your boiler is over 10 years old and needs frequent repairs, replacement is usually more cost-effective. Modern boilers are also significantly more energy efficient — an A-rated boiler could save £200–£300 per year on gas bills compared to an old G-rated model.
Yes, it is a legal requirement. All gas boiler installations, repairs, and servicing must be carried out by a Gas Safe registered engineer. You can verify an engineer's registration at GasSafeRegister.co.uk. Never accept work from an unregistered installer.