How Often Should a Boiler Be Serviced?

An annual service is the standard recommendation for every gas boiler, regardless of age or brand — here's why that specific interval, not "whenever it seems to need it".

Why every 12 months specifically

  • Most boiler manufacturers (including Worcester Bosch, Vaillant, and Baxi) require proof of an annual service to keep the manufacturer warranty valid — missing a year can void years of remaining cover.
  • A yearly interval catches wear (seals, heat exchanger, safety devices) before it becomes a breakdown, rather than after.
  • It's also the same check that verifies your boiler isn't producing dangerous carbon monoxide — not something to leave for longer than a year.

What's actually checked

  • Visual inspection of the boiler and flue, combustion analysis and burner efficiency, gas pressure and flow rate, heat exchanger inspection, and safety device testing (overheat thermostat, pressure relief valve) — see our boiler servicing page for the full list.

What if you skip a year?

  • The immediate risk is safety — a fault that would have been caught goes unnoticed for another year.
  • The financial risk is the warranty: most manufacturers can refuse a claim if there's a gap in your service record.
  • It also tends to be a false economy — a caught-early fault is usually a much smaller repair than the breakdown it would otherwise become.

Frequently asked questions

Written and carried out by Muhammad Imran, Gas Safe Registered Engineer (Reg. No. 669298). Last updated 2026-07-18.

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