Boiler Service Cost & How Often to Service
An annual boiler service is one of the cheapest pieces of preventative home maintenance you can buy — and one of the most important for safety, efficiency, and keeping your warranty valid. This guide covers exactly what it should cost, what a real service includes, and how often to book.
7 minute read · Updated June 2026 · UK guidance
Quick answer
A UK boiler service typically costs £80–£120 and should be carried out once every 12 months by a Gas Safe registered engineer. Annual servicing keeps the manufacturer warranty valid, maintains efficiency, and is essential for carbon monoxide safety. A proper service uses a flue gas analyser and follows the manufacturer checklist — not just a visual look.
What Is Included in a Proper Boiler Service?
A genuine annual service is far more than lighting the boiler and checking it fires. A Gas Safe engineer following the manufacturer schedule should carry out the following:
- Visual inspection of the boiler and flue for damage, corrosion, and correct installation
- Checking gas pressure and flow against the manufacturer specification
- Testing flue gases for carbon monoxide and combustion efficiency with a flue gas analyser
- Inspecting and cleaning key internal components (heat exchanger, burner, ignition)
- Checking seals, the condensate trap, and electrical connections
- Testing safety devices and controls operate correctly
- Confirming the gas appliance is safe to use and issuing a service record
If a quote is suspiciously cheap, ask whether a flue gas analyser is used and whether the engineer follows the manufacturer checklist. A service without combustion analysis is not a real service.
Why Annual Servicing Pays for Itself
It keeps your warranty valid. Almost every manufacturer warranty (typically 5–10 years) is conditional on a documented annual service. Skip a year and you may have no cover when an expensive part fails.
It prevents the expensive breakdown. Servicing catches a sticking valve, a failing pump, or a blocked condensate trap before it becomes a no-heat emergency in January — when callout demand and prices peak.
It protects your bills. A clean, correctly pressured boiler burns gas more efficiently. A poorly maintained boiler quietly wastes energy every single day.
It is a safety check. A cracked heat exchanger or blocked flue can leak carbon monoxide — a colourless, odourless gas that kills. The service includes a combustion test specifically to catch this. Always pair an annual service with a working carbon monoxide alarm.
One-Off Service vs Boiler Cover Plan
A one-off service at £80–£120 is the right choice if your boiler is relatively new, under manufacturer warranty, and you have an emergency fund for repairs.
A boiler cover plan (a monthly subscription that bundles the annual service with breakdown repairs) can make sense for older boilers out of warranty, where a single major repair would hurt. Compare the annual cost of the plan against the realistic repair risk — and always check the excess and what is excluded.
Frequently Asked Questions
How much does a boiler service cost?
A standalone annual boiler service in the UK typically costs £80–£120. Prices are higher in London and the South East, and lower if the service is bundled into a boiler cover plan. Beware of very cheap "services" that are really just a visual glance — a proper service uses a flue gas analyser and follows the manufacturer checklist.
How often should you service a boiler?
Once a year. Most boiler manufacturers require annual servicing to keep the warranty valid, and most home insurers and landlord regulations expect it too. Annual servicing catches faults early, keeps the boiler running efficiently, and is essential for carbon monoxide safety.
Is a boiler service a legal requirement?
For homeowners it is not a legal requirement, but it is strongly recommended and usually a condition of the manufacturer warranty. For landlords it is different: a Gas Safety Certificate (CP12) covering all gas appliances is a legal requirement every 12 months, carried out by a Gas Safe registered engineer.
Who can service a boiler?
Only a Gas Safe registered engineer can legally work on a gas boiler in the UK. Always ask to see their Gas Safe ID card, which lists exactly which appliances they are qualified to work on. You can verify any engineer at gassaferegister.co.uk.
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