# Should I repair or replace my boiler?

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

The rule of thumb: under about 10 years old with a single, non-major fault — repair. Beyond the 10–15-year mark, or facing a big-ticket part (heat exchanger, PCB, fan) on top of rising bills and repeat call-outs — replacement often wins on total cost. The two questions that settle most cases: is the failed part a major one, and are parts still available for your model? A discontinued boiler needing a heat exchanger is a replace; a five-year-old boiler needing a diverter valve is a repair. We quote both, every time, and let you choose with the real numbers.

## When repair is the right call

A relatively young boiler (say, under 10) with a well-defined, cheaper fault — a valve, a sensor, a pump — is worth repairing. It's sound, parts are available, and a new boiler wouldn't pay for itself. Replacing it would be selling you something you don't need, which we won't do.

## When replacement wins

Age beyond 10–15 years, a major component failure, discontinued parts, falling efficiency and repeat breakdowns for different faults — any two of those together and the maths tips. A new boiler comes with a fresh warranty and, under Approved Document L, must meet 92% (ErP) efficiency in an existing home — before you count the avoided emergency call-outs.

## The honest number we give you

We diagnose the actual fault, then quote the repair and a like-for-like replacement side by side — including the efficiency difference and the warranty you'd gain. No pressure, no scare tactics; the decision is yours, made on real figures rather than a doorstep sales pitch.

> Two questions settle it: is the failed part a major one, and can you still get parts? We quote both routes every time — the decision should be yours, made on real numbers.
>
> — David, Founder, Datum

## Related questions

### Is it worth repairing a 12-year-old boiler?

Depends on the part. A cheap component on an otherwise sound unit, maybe. A major part like a heat exchanger — that money usually goes further into a new boiler with a 10-year warranty. We show you both numbers so it's your call.

### Do new boilers really save enough to justify the cost?

It depends on the old boiler and how much gas you use. Approved Document L expects a replacement boiler to meet 92% (ErP) efficiency, and we'll estimate the saving from your actual gas bills rather than quote a sales figure.

### What if parts for my boiler are discontinued?

That's often the deciding factor. If the part you need is no longer made, a repair can be impossible or hugely marked-up, and replacement becomes the sensible route. We tell you straight if your model's there.

## 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)

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