# How long does a boiler last — and when should I replace mine?

*David · Founder, Datum · Datum · updated 2026-10-19 · Boilers*

Baxi says a boiler lasts 10 to 15 years if it is serviced annually and looked after properly — some soldier on longer, but parts can get harder to find past that point. The rule of thumb: under 10 years old with a single fault, repair; beyond 10–15 with rising bills, repeat faults or discontinued parts, replacement often wins on total cost. The worst option is the one most people choose: waiting for the fatal breakdown on the coldest week of the year.

## The warning signs worth acting on

Repeat call-outs for different faults, yellow or lazy flame behaviour flagged at service, rising gas use for the same warmth, pressure that won't hold, and parts on back-order. Any two of those together is the boiler telling you its plans.

## Why efficiency shifts the maths

Approved Document L expects a replacement gas boiler in an existing home to meet 92% (ErP) efficiency. An older boiler may fall well short of that, so we estimate the saving from your own gas bills rather than quote a generic figure — before you count the avoided emergency call-outs.

## Planned beats emergency, every time

A planned replacement is a surveyed, fixed-price, one-day job with the right boiler chosen calmly. An emergency replacement is whatever's in stock, fitted at distress speed, in a cold house. Same boiler, very different experience and price.

> Boilers rarely die quietly — repeat call-outs, rising gas use, parts on back-order. Any two of those together is the boiler telling you its plans.
>
> — David, Founder, Datum

## Related questions

### Should I repair a 14-year-old boiler?

If it's a cheap part and the boiler's otherwise sound, maybe. If it's a major component (heat exchanger, PCB), putting that money into a new boiler with a 10-year warranty usually wins. We quote both and let you decide.

### Does an annual service really extend boiler life?

Yes — it keeps combustion at spec, catches small faults early, and keeps the warranty valid. It's the cheapest life-extension there is.

### How long does a replacement take?

A like-for-like swap is usually one day, including flush, controls and handover.

## Sources & verification

- [Baxi — How long does a boiler last? ("10 to 15 years if you have it serviced annually and look after it properly"; accessed 19 Oct 2026)](https://www.baxi.co.uk/help-and-advice/faqs/how-long-does-a-boiler-last)
- [Baxi — warranty terms (register within 30 days of installation or commissioning; an annual service in line with the instructions keeps it valid; verified 27 Oct 2026)](https://www.baxi.co.uk/professional/services/warranty)
- [GOV.UK — Approved Document L, volume 1: dwellings (before a new heating appliance is installed the central heating and primary hot water circuits should be thoroughly cleaned and flushed, a chemical inhibitor added, the feed water to combination boilers treated in hard water areas, and the system commissioned to BS 7593 — paragraph 8.8 of the 2021 edition incorporating 2023 amendments, 7.8 of the 2026 edition; a replacement gas boiler in an existing dwelling should meet 92% ErP efficiency, or in exceptional circumstances 78% SEDBUK; accessed 19 Oct 2026)](https://www.gov.uk/government/publications/conservation-of-fuel-and-power-approved-document-l)
- [GOV.UK — Planning permission: after you apply (most applications are decided within 8 weeks; 13 weeks in England for unusually large or complex applications; verified 27 Oct 2026)](https://www.gov.uk/planning-permission-england-wales/after-you-apply)

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