How often should a boiler be serviced?
A boiler should be serviced once every 12 months. It is a condition of almost every manufacturer warranty, it is a legal duty for landlords, and it is the only reliable way to catch a failing part before it leaves you without heating in January.
How often a boiler should be serviced, by situation
| Situation | How often | Why |
|---|---|---|
| Owner occupied home, boiler in warranty | Every 12 months | Missing a service usually voids the manufacturer warranty |
| Owner occupied home, boiler out of warranty | Every 12 months | An annual check still catches worn parts and unsafe flue conditions early |
| Rented property | Every 12 months, by law | Landlords must hold a Gas Safety Record renewed annually |
| Boiler over 10 years old | Every 12 months, without fail | Older parts fail more often and replacement parts get harder to source |
| Boiler used seasonally or in a holiday let | Every 12 months, before the heating season | Long idle periods let seals dry out and pressure drop unnoticed |
What a proper service includes
A genuine annual service is more than a quick look. Your engineer should check the following, and give you a written record of what they found.
- Flue and combustion readings, to confirm the boiler is burning safely and not producing carbon monoxide.
- Gas pressure and gas rate, checked against the manufacturer's figures for your model.
- Seals, the heat exchanger and the burner, cleaned and inspected for corrosion or blockage.
- System pressure and the expansion vessel, topped up and re-charged if needed.
- Safety devices and controls, tested rather than assumed to work.
What it costs and when to book
A standalone annual boiler service in the UK typically costs about £80 to £120, or it is bundled into a monthly cover plan. Book it in late summer or early autumn if you can. Engineers are least busy then, and a fault found in September is an inconvenience rather than an emergency in December.
Is a service the same as a repair?
No. A service is a scheduled safety and efficiency check on a working boiler. A repair fixes a boiler that has already failed. If your boiler is currently not working, that is a repair call, and you can read our guidance on who to call when your boiler is not working or on whether it is worth repairing a boiler at all.
All gas work, servicing included, must be carried out by a Gas Safe registered engineer. You can ask to see the engineer's Gas Safe ID card before they start, and check the registration number on the Gas Safe Register.