A boiler service is a yearly inspection by a qualified engineer: checking the boiler and its controls, testing for leaks, confirming the pressure is correct, and checking the flue is venting safely. It's a safety and performance check, not a repair. A gas boiler service in the UK costs £80 to £120 on average, and we'll pass your enquiry to a local Gas Safe registered engineer who can book you in.
This page covers what's included, how often you need one, who's allowed to do the work, and what it costs by boiler type.
Do radiators get checked during a boiler service?
A standard boiler service covers the boiler itself, not every radiator individually. The engineer inspects the boiler and its controls, checks for leaks, confirms the system pressure, and tests the flue. If you want radiators checked too, a power flush or a separate central heating check covers that.
Some engineers will bleed a radiator or two as part of a wider visit if you ask, but it isn't part of a standard service. If your radiators are cold at the top, slow to heat up, or the system sounds noisy, that's usually a sign of air or sludge in the system rather than something a boiler service fixes on its own.
Do you need to service a gas boiler every year?
An annual service isn't a legal requirement if you own and live in your own home, but it's usually required to keep the manufacturer's warranty valid, and it's the main way to catch a developing fault before it becomes a breakdown. Most manufacturers ask for proof of an annual service, by a Gas Safe registered engineer, to keep a boiler's warranty valid.
It's a different thing to a landlord's gas safety check. If you rent your property out, the law requires an annual gas safety check (a Gas Safety Record, sometimes called a CP12) on every gas appliance, separate from a full boiler service, though many landlords book both at once.
Can anyone service a Vaillant boiler?
No. By law, only a Gas Safe registered engineer can service a gas boiler, including a Vaillant. Gas Safe Register is the official body for gas engineers in the UK, and you can check anyone's registration number on their website or by calling 0800 408 5500 before they start work.
For a Vaillant specifically, using an engineer who's also a Vaillant-accredited installer can matter if the boiler's still under its manufacturer warranty, since some warranties ask for an accredited engineer's stamp. A local Gas Safe engineer can tell you whether that applies to your boiler.
Questions people ask
How often should a boiler be serviced?
Once every 12 months, for gas, oil and electric combi boilers alike. Regular servicing keeps the boiler safe, helps it run efficiently, and is usually a condition of the manufacturer's warranty. Oil boilers should be serviced by an OFTEC qualified engineer rather than a Gas Safe one.
How much does a boiler service cost in the UK?
A gas boiler service averages £100, typically £80 to £120. Oil boiler services average £92.50 (£75 to £110), and electric combi boilers average £90 (£70 to £110). Annual boiler and heating cover, which usually includes breakdown support as well as a service, runs £180 to £300 a year, or around £8 to £13 a month.
What's included in a boiler service?
A visual inspection of the boiler and its controls, a check for leaks or wear, a safety check, and a test that the system's working correctly. For gas boilers, the engineer also checks the system pressure and tests the flue. A typical visit takes 40 to 60 minutes.
Can you service a boiler yourself?
No. Servicing a gas boiler is work that must be carried out by a Gas Safe registered engineer, by law. You can do simple checks yourself between services, like keeping an eye on the pressure gauge and looking for visible leaks, but the service itself is a professional job.
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