New Boiler Cost UK (2026 Guide)
A new boiler installed in the UK in 2026 typically costs £1,800–£2,800 for a like-for-like combi swap, £2,500–£4,000 for a cylinder-to-combi conversion, and £2,800–£4,500 for a system boiler with an unvented cylinder. Where you land inside those bands depends on the boiler's brand tier, the warranty length, flue complexity and how much of the surrounding system needs bringing up to standard — and the fastest way to be overcharged is not knowing which of those you're paying for.
Installed prices by job type
The like-for-like combi swap is the benchmark job: same fuel, same location, modern boiler onto an existing system. Budget brands (Alpha, Glow-worm) land £1,600–£2,200 installed; mid-market (Ideal, Baxi, Potterton) £1,700–£2,600; premium (Worcester Bosch, Vaillant, Viessmann) £2,000–£3,300. The appliance itself is often only 40–55% of the invoice — the rest is labour, flue, filter, controls, chemicals and the commissioning paperwork.
Conversions cost more because more changes: moving from a heat-only boiler with tanks to a combi means removing the cylinder and loft tanks, rerouting pipework and upgrading the gas supply pipe in many cases — £2,500–£4,000 is the honest band. A system boiler with a new unvented cylinder runs £2,800–£4,500, with cylinder size and location driving the spread. Relocating any boiler adds £300–£800 for flue and pipe runs.
What a proper quote includes
A complete quote lists: the boiler model and warranty length, flue and any plume kit, a magnetic system filter, controls meeting current regulations, a chemical cleanse (or powerflush where sludge justifies it), condensate connection, removal and disposal of the old appliance, commissioning with the benchmark record, and building-control notification. If a quote undercuts the market noticeably, read it against that list — the gap is usually one of these quietly missing.
Itemisation is your negotiating position: when you can see the filter, the controls tier and the cleanse as line items, you can compare quotes like-for-like and query individual figures. A single-line 'supply and fit boiler £X' quote gives you nothing to compare and the installer everything to flex. Network quotes itemise as standard — insist on the same from anyone else quoting.
What moves the price up or down
Upward pressure: longer warranties (10–12 year tiers cost more up front and are usually worth it), difficult flue routes (internal boilers, tall buildings, plume management near boundaries), gas pipe upgrades where the existing run is undersized for a modern combi, and sludged systems needing a full powerflush rather than a cleanse. Downward pressure: genuine like-for-like simplicity, off-season booking (installers discount quiet months — spring especially), and reusing sound existing controls where they meet regulation.
Timing matters more than haggling: January quotes carry distress premiums because demand does; May quotes compete for work. If your boiler is limping but alive, quote in spring and schedule at leisure. The single most expensive way to buy a boiler is cold, in a cold house, from the first available installer.
Finance, warranties and whole-life cost
Boiler finance spreads £2,000-plus over years — compare the total repayable, not the monthly figure, and remember a 0% offer priced into a higher install cost isn't 0%. On warranties: the long tiers (10–12 years) effectively insure the boiler's whole realistic first life, conditional on documented annual servicing — budget the service into the whole-life arithmetic because skipping it voids the cover.
Whole-life thinking changes brand choices: a budget boiler at £1,700 with a 7-year warranty and earlier component wear versus a premium unit at £2,400 with 12 years covered is a closer race than the sticker gap suggests — and in hard-water areas without scale protection, closer still. Our brand hub compares the tiers honestly; the installation quality, though, outweighs the badge every time.
| Job | Typical range | Notes |
|---|---|---|
| Like-for-like combi swap | £1,800–£2,800 | Same location, existing system sound |
| Budget brand combi swap | £1,600–£2,200 | Alpha, Glow-worm tiers |
| Premium brand combi swap | £2,000–£3,300 | Worcester, Vaillant, Viessmann |
| Cylinder-to-combi conversion | £2,500–£4,000 | Tank/cylinder removal, pipe rework |
| System boiler + unvented cylinder | £2,800–£4,500 | Cylinder size drives spread |
| Boiler relocation add-on | £300–£800 | New flue and pipe runs |
How to use these price bands
Treat the ranges above as calibration, not quotation: your job sits somewhere in the band depending on access, boiler brand, system condition and region, and a written quote after a survey is the only number that binds anyone. The practical use of national bands is spotting outliers — a quote far above the range deserves a written justification, and one far below usually has the missing money hiding in exclusions. Ask what's included, whether a system cleanse and magnetic filter are in the price, and how any extra time is charged.
Frequently asked questions
Why do boiler quotes vary so much for the same job?
Different inclusions: warranty tier, filter, controls, cleanse level and paperwork all vary quote to quote. Itemised quotes make the differences visible; single-line quotes hide them. Compare the list, not the headline.
Is a cheap boiler installation a false economy?
It can be, in two ways: missing inclusions (no filter, no proper cleanse) that shorten the boiler's life, and rushed commissioning that voids warranty conditions. Cheap and complete exist — but verify the completeness.
When is the cheapest time to buy a boiler?
Spring and early summer, when installer diaries empty and quotes compete. Winter distress purchases pay a demand premium. If your boiler is ageing, quote before it forces the timing.
Do I have to use the boiler brand's own installers?
No — any Gas Safe registered installer can fit any brand. Manufacturer-accredited installers can offer the longest warranty tiers, which is worth weighing, but accreditation is about warranty access, not legal permission.
Where written advice reaches its limit
Guidance like this can tell you what usually causes a symptom, but only an engineer with instruments on your actual appliance can confirm it. If what you're seeing doesn't quite match any pattern described here — or matches several at once — that ambiguity is itself useful information to hand over. Our engineers do this triage daily, and an honest one will tell you on the phone when your problem sounds like a cheap fix, a bigger job, or something that isn't the boiler's fault at all.
Carbon monoxide safety: symptoms, alarms and what to do — essential reading for every home with a fuel-burning appliance.