How often should you service your boiler?

Why annually?

• Safety: the service checks for carbon monoxide risks, flue problems and gas leaks.
• Warranty: virtually every manufacturer requires documented annual servicing to keep it valid.
• Efficiency: a tuned boiler burns less gas, and small losses compound on every heating bill.
• Reliability: worn parts get spotted in September, not at 7am on the coldest day in January.

What a proper service includes

• Visual inspection and casing checks, then flue gas analysis to confirm safe, efficient combustion.
• Checks on gas pressure and flow, seals, electrodes, condensate trap and safety devices.
• Cleaning of key components where the manufacturer specifies it.
• A written record of the work, kept as your warranty evidence.

When to book, and what it costs

Engineers are busiest from the first cold snap until spring. Booking your service in summer or early autumn means easier appointments and gives you a full heating season of confidence. Typical UK pricing in 2026 is £80–£120 for a standard service; combining it with a landlord gas safety check in one visit usually costs less than booking both separately.

Signs your boiler shouldn't wait for its annual service

• Yellow or lazy flame instead of crisp blue. Stop using it and get it checked.
• New banging, kettling or gurgling noises.
• Pressure that needs topping up more than occasionally.
• Radiators heating unevenly or hot water running lukewarm.

Quick questions