How Often Should a Boiler Be Serviced?

Why annual servicing is the standard recommendation, how it protects warranties, and the warning signs that mean you should not wait.

Last updated: 2026-10-19

Once a year is the standard recommendation for a domestic boiler service, and it is what most manufacturers require to keep a warranty valid.

Why annually?

A boiler service is a planned inspection, not a repair. It checks that the appliance is burning correctly, that the flue and ventilation are sound, and that safety devices work. Small issues — a weeping seal, a partially blocked condensate, combustion drifting out of tolerance — are much cheaper to catch at a service than after a breakdown.

An annual rhythm also means the engineer sees the boiler year on year and notices changes that a one-off visit would miss.

What about warranties?

Most manufacturer warranties require annual servicing by a competent, Gas Safe registered engineer, with records kept. Check your own warranty terms — the exact requirements vary by brand and by whether it is a product warranty or an extended one. Keep the service paperwork; without it, a warranty claim can be refused.

Do landlords need more?

Landlords have a separate legal duty: an annual gas safety check on every gas appliance and flue in a rented property, recorded on a CP12. Servicing and the CP12 are different jobs, although they can usually be done in the same visit. See our landlord gas safety guide.

When not to wait a year

Book sooner if you notice:

• a yellow or lazy flame instead of a crisp blue one;
• soot or staining around the boiler or flue;
• repeated lockouts or fault codes;
• pressure that keeps falling;
• unusual noises such as kettling or banging;
• headaches, nausea or drowsiness when the heating has been on — treat this as a possible carbon monoxide warning and act immediately (see our carbon monoxide guide).

How to book

Gather your boiler make and model, your postcode and any service history. Our boiler servicing page explains what happens on the day.