How often should you service your boiler?
It's easy to put off — the boiler's working, so why bother? Here's why an annual service is worth booking anyway, and what actually happens during one.
Quick answer
Once a year, every year, regardless of whether anything seems wrong. It keeps your manufacturer's warranty valid, catches small faults before they turn into breakdowns, and — for landlords — is a legal requirement alongside your annual gas safety certificate.
Why annual, specifically?
Boiler manufacturers set servicing intervals as a condition of their warranties, and almost all of them specify once every 12 months. Skip a year and you can invalidate the warranty entirely — meaning if something expensive fails two years in, you're paying full price for a repair that should have been covered.
There's a safety angle too. Boilers burn gas to produce heat, and a fault in the flue or heat exchanger can allow carbon monoxide into your home — a gas that's colourless and odourless. A service includes checks specifically designed to catch that kind of fault before it becomes dangerous, not just to keep the boiler running efficiently.
What actually happens during a service
- Full visual inspection and clean of the main components
- Flue and ventilation check for safe operation
- Gas pressure and burner performance tested
- Seals, condensate trap and pipework checked for leaks
- Heating and hot water function tested end to end
- A written record left with you — useful for warranty claims, home insurance, or landlord compliance
It typically takes 30–45 minutes for a straightforward job, longer if anything needs adjusting along the way.
What happens if you skip it
Nothing, usually — until something does go wrong. The most common pattern is a small issue (a slightly dirty burner, a seal starting to weep, a sensor drifting out of calibration) going unnoticed for a year or two until it causes a breakdown that would have been a five-minute fix if it had been caught early. By that point you're looking at a call-out plus parts, rather than a routine service fee.
If you're a landlord, this is separate from — but related to — your legal obligation to have a CP12 gas safety certificate renewed every 12 months for any rented property with gas appliances. Many landlords book both at the same time to save on call-outs.
When's the best time to book?
Any time of year technically works, but late summer to early autumn is the sweet spot — you catch any issues before the boiler's working hard through winter, and you avoid the queue that builds up once the weather turns cold and everyone's boiler decides to fail at once.
Ready to book your service?
Annual boiler services start from £60. Message Ash with your postcode and boiler type for a time that works.