Boiler quotes confuse people because two homes can be quoted thousands of pounds apart for 'a new boiler' — and both quotes can be fair. The price is really three things: the boiler itself, the complexity of the installation, and what's included around it.
Here's how the numbers break down in 2026, and the questions that keep a quote honest.
Typical price ranges
A straightforward combi-for-combi swap (same location, same type) typically lands between £1,800 and £3,000 including installation, depending on the boiler brand and size. A system or heat-only boiler replacement usually runs £2,000–£3,500. Converting from a conventional cylinder setup to a combi — which involves removing tanks, rerouting pipework and more labour — commonly costs £3,000–£4,500. Relocating the boiler adds several hundred pounds or more for flue and pipe runs.
What changes the price
The big variables: boiler brand and output (a 30kW+ boiler for a large house costs more than a 24kW for a flat), conversion vs straight swap, boiler location and flue complexity, condensate drainage options, and your home's pipework condition. Extras that are worth paying for: a magnetic filter, a full system flush, and smart controls. Extras that pad quotes: overly long 'while we're at it' lists — ask what each line actually does.
What a proper installation includes
A professional installation should include: removal and disposal of the old boiler, a system cleanse or powerflush (contaminated water kills new boilers), a magnetic filter, inhibitor chemical, gas rate and safety checks, Building Regulations notification, manufacturer warranty registration, and a benchmark commissioning record. If a quote is dramatically cheaper, check which of these is missing.
Which brand?
Worcester Bosch and Vaillant lead on reliability and warranty support and price accordingly; Ideal, Baxi and Glow-worm offer strong value tiers. Warranty length matters — many boilers carry 7–12 year manufacturer warranties when installed by accredited installers and serviced annually. A long warranty from a solid brand is worth a modest price premium.
Repair or replace?
The rule of thumb: if your boiler is over 10–12 years old and facing a repair of several hundred pounds, replacement usually wins on economics — new boilers are meaningfully more efficient and start a fresh warranty clock. Under 8 years old with a first-time fault? Repair, almost always. We'll show you both numbers and let you decide.
