BOILERS GUIDE
Boiler Replacement Cost 2026: Install, Pipework & Removal Charges
Replacing a boiler costs £2,000 to £4,500 fitted in the UK in 2026, including removal of the old unit and basic install.
Check eligibilityLast updated May 2026
Replacing a boiler costs £2,000 to £4,500 fitted in the UK in 2026, including removal of the old unit and basic install.
Answer a few quick questions to see which government energy grants you're eligible for. Free, instant results.
Replacing a boiler costs £2,000 to £4,500 fitted in the UK in 2026, including removal of the old unit and basic install. The price depends on whether you stay with the same boiler type, change location or upgrade size. ECO4 can cover the full cost if you qualify on benefits and EPC band, and a like-for-like swap typically sits at the lower end of that range. See our guide on government scheme for old boilers for more detail.
"Replacement" sounds simple. The quote often isn't.
A genuine replacement quote should cover the lot: removal and disposal of the old boiler, the new boiler unit, a new flue (current Part L regulations mean old flues rarely meet spec on a like-for-like swap), basic pipework adjustments, a Part L system flush, a magnetic filter, commissioning and registration with the Gas Safe Register, owner manual handover, building regs notification and warranty registration. That's the working definition of a "fitted" replacement in 2026.
Removal and disposal sometimes gets billed separately. Most reputable installers fold it into the headline price, but a few list it as £80 to £150 extra on the final invoice. Worth confirming before the engineer rolls up with a skip.
The new flue almost always has to be new. Old flues on boilers more than 10 to 15 years old rarely satisfy current proximity rules to windows, doors, soffits or neighbouring properties, and the manufacturer's warranty on the new boiler won't cover a reused flue anyway. Don't agree to keep the old one.
System flush and magnetic filter are now Part L requirements on most replacements. Some "cheap" replacements quietly skip both. Skipping either voids the boiler manufacturer's warranty in most cases (Worcester Bosch, Vaillant and Ideal all require both as install conditions), which means the £150 you "saved" turns into a £600 bill the first time a pump or heat exchanger fails. Always confirm both are in writing on the quote.
Commissioning is the bit a lot of homeowners don't see but matters most for warranty purposes. The engineer registers the new boiler with the manufacturer, files the Gas Safe notification, completes the benchmark commissioning checklist and gives you the building regs compliance certificate. If you can't find that paperwork in your kitchen drawer six months later, something's wrong.
Honest opinion: the cheapest replacement quote on the table almost always has the system flush, the magnetic filter or both missing from the line items. Once you add them back in, the price gap usually closes.
The cheapest replacement is always like-for-like in the same location with the same brand. The most expensive is a configuration change.
Like-for-like (combi to combi, same brand, same wall): typically £2,000 to £3,000. Most jobs sit here. The pipework, gas connections, flue position and condensate drain don't move, which collapses the labour time. A competent two-person team finishes the job in 6 to 8 hours, and the bigger installer chains can sometimes get it done in a single morning.
Conventional to combi conversion: £3,000 to £4,500. This pulls out the hot water cylinder, the cold water tank in the loft, the airing cupboard plumbing and the gravity-fed pipework. New mains pressure pipework runs to bathrooms and kitchen. The cylinder cupboard becomes available space again. The loft tank disappears. Two days minimum. Worth it for the extra cupboard space alone in a lot of older terraces. The downside, which most installers won't lead with: a combi runs both heating and hot water from a single unit, so when it fails you lose both at once.
Upgrade in output or efficiency: £2,500 to £3,500. Same configuration, newer model with a longer warranty, often paired with a smart thermostat. A 9-year-old Worcester Greenstar 24i swapped for a current Greenstar 4000 with a Wave thermostat lands here. Not strictly necessary but the warranty jump from 5 to 12 years materially shifts the value.
Brand switch: usually £100 to £300 on top. Some installers carry stock and parts familiarity for one or two brands and price the others higher to compensate. If your installer is a Worcester accredited partner and you're asking for an Ideal, expect a quote that nudges the price up. Worth asking for it itemised. Worth not paying if the gap looks invented.
A small but useful thing we see in real quotes: some installers offer £100 to £200 off if you agree to dispose of the old boiler yourself rather than letting them include it. Not always advertised. Worth asking.
The headline replacement price is rarely the final invoice. The variables sit underneath.
Power flush. £300 to £500 if the existing system has sludge or corrosion. Boilers more than 10 years old without a magnetic filter almost always need one. The new boiler's warranty depends on it.
New thermostat. £100 to £300 for a smart unit (Hive, Nest, Tado are the three you'll see quoted most). Some installers bundle it free for the marketing angle. Others list it as an optional extra.
Replacement radiators. £80 to £250 each if the existing ones are corroded or showing pinhole leaks. Often only flagged once the system's been drained, which means a mid-job phone call asking for sign-off on extra work. Not a scam. Just an unwelcome surprise.
Boiler relocation. £300 to £800 for moving the boiler to a different wall. New pipe runs, flue reroute, sometimes a fresh hole through external brickwork. The most common reason for moving: getting it out of a kitchen cupboard for noise reasons. The least common: aesthetic preference.
Removal of redundant tank or cylinder. £150 to £400 in conversion jobs. Old cylinders are heavy and often awkward to get out without disturbing pipework. Loft cold-water tanks are easier but still take an hour.
Building regs notification fee. £100 to £200. Almost always built into a reputable installer's price. Sometimes added separately by aggregator-style "fixed price" installers who use the headline to win the lead.
Of these, the power flush is the one most worth proactively asking about. The others are usually self-evident at survey stage. The flush is the one some installers genuinely hope you won't notice until they're invoicing.
This is where most cost guides go quiet and where the £1,000 of difference usually lives.
Independent local installers come in 15 to 30% cheaper than national chains for the same boiler in the same property. A Worcester Greenstar 4000 fitted by an independent in Leeds is typically £2,400 to £2,800. The same boiler fitted by British Gas or a national brand under similar terms is more like £3,200 to £3,800. The premium buys you a longer warranty (sometimes 10 versus 7 years), brand-name reassurance and finance options that smaller installers can't match.
National brands sit at the top end deliberately. British Gas, BOXT, Heatable and similar names compete on convenience, warranty length and finance, not on raw price. For someone who values fixed-price simplicity and doesn't want to chase three quotes, the premium is rational. For anyone happy to vet three local quotes, it's money out the window.
ECO4-approved installers fit replacements free if you qualify. The installer is funded by an energy supplier (British Gas, OVO, EDF, Octopus or Scottish Power, mainly) and the homeowner pays nothing for the boiler, flue or install. The trade-off: you usually can't pick the brand, and the installer is chosen by the funding pathway, not you. For households on Universal Credit or Pension Credit with an EPC band D or below, it's the cheapest possible route by a wide margin.
Honest position: British Gas quotes are 25 to 40% higher than independent installers for the same boiler. The difference buys you brand assurance, longer warranties and predictable finance terms. Worth it for some buyers, not for others. Don't assume a national chain is always the safer choice. The Gas Safe Register is the same legal standard whether the engineer wears a Worcester van uniform or a small-business polo shirt.
We've seen homeowners reflexively go to British Gas because the parent company is familiar, then discover six months later that the boiler is an Ideal Logic, the warranty is 7 years (which they could have got at any independent installer) and they paid £1,200 more than necessary. The flip side: we've also seen ECO4-funded replacements end with a brand the homeowner wouldn't have chosen, in a position they didn't love, with a thermostat they didn't ask for. Free comes with its own constraints. Anyway, the trade-off is real on both sides.
Three live routes in 2026.
ECO4 covers the full cost of a boiler replacement if your household qualifies. Eligibility hinges on a qualifying benefit (Universal Credit, Pension Credit, Income Support and others) and an EPC rating of D or below. According to GOV.UK ECO4 guidance, the scheme is administered by the major energy suppliers and runs until December 2026. About a third of UK households meet the criteria according to Energy Saving Trust figures.
Pensioners on Pension Credit have a specific route through ECO4 that catches more households than people expect. We cover it in detail in our pensioner boiler grants guide, including the gap between actual eligibility and the number of pensioners claiming the underlying benefit.
Warm Homes Local Grant: varies by council. Some authorities include boiler measures, others restrict to insulation only. Sheffield and Cornwall councils have included replacement boilers in recent rounds. Manchester has not. The funding gets allocated to local authorities and each one chooses its own focus.
For the new-build cost side of the question (rather than the replacement angle), see our companion piece on new boiler cost. The numbers overlap heavily, the framing differs.
Open the eligibility checker before you commit. Two minutes. If ECO4 covers your replacement, the £3,000 you were about to spend stays in your account. If it doesn't, you'll still see which other grants apply and which questions to put to your installer before the engineer arrives.
For the wider picture on boiler grants and options, the boilers hub collects everything in one place.
Common questions