Boiler guide · 4 min read · Updated October 2026
What a boiler service costs — and why it protects your warranty
What a proper annual service includes, what it typically costs, and why skipping it can void the manufacturer warranty you paid for.
What a service actually is
An annual service is a qualified engineer stripping the boiler far enough to check the burner, heat exchanger, seals, flue and combustion, then cleaning and re-commissioning it. It is not a quick glance and a sticker.
- Combustion check with a flue gas analyser
- Burner and heat exchanger inspection and clean
- Condensate trap and pipework check
- Gas pressure and tightness verification
- Service record completed — keep this, it is your warranty evidence
What it costs
Across the UK, a standard boiler service typically costs somewhere between £80 and £120 depending on region and boiler type. London sits towards the top of that range. Anything dramatically cheaper usually means the combustion check is being skipped.
The warranty connection most people miss
Almost every long manufacturer warranty — Vaillant's extended terms, Worcester Bosch's 10 and 12-year options, Ideal's 10-year cover — is conditional on annual servicing by a qualified engineer. Miss a year and the extended cover can lapse, leaving you on the short standard term or nothing at all.
Keep every service record. If you ever claim, the manufacturer asks for them.
Common questions
How often should a boiler be serviced?
Once a year. Every extended manufacturer warranty we have researched requires annual servicing as a condition of cover.
Does a new boiler need servicing in its first year?
Yes. The first service is usually due 12 months after commissioning, and skipping it can break the warranty conditions from year two onwards.
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