Boiler Service vs Boiler Repair – What’s the Difference?

A typical boiler service involves a thorough inspection of your boiler by a Gas Safe registered engineer. The engineer will remove the boiler casing to check and clean internal boiler parts such as the burner, main injector, and heat exchanger. They will also run safety checks on critical components, test the pilot light, and check ventilation to ensure there are no dangerous blockages. Gas pressure, flow, and emissions are measured to confirm the boiler is burning fuel correctly and not producing unsafe levels of carbon monoxide. At the end of the appointment, you should be given a service report that outlines what was checked, cleaned, or adjusted, along with any recommendations for minor problems or future breakdowns to watch out for.

Yes, an annual boiler service is highly recommended for homeowners and is a legal requirement for landlords. For landlords, a yearly gas safety certificate must be issued for all gas appliances in the property, including the boiler. For homeowners, while not legally required, an annual check provides an important safety measure against hazards such as carbon monoxide poisoning and gas leaks. Servicing also helps reduce energy bills by keeping your boiler efficient. In addition, many boiler warranties state that the first year of an annual boiler service must be completed and then continued every year to keep the warranty valid. Skipping servicing could invalidate cover, meaning you would have to pay the full boiler service cost or expensive repair bills if something goes wrong.

If your boiler is working normally, producing hot water, and running without faults, then it likely only needs its routine annual service. This preventive regular maintenance is designed to catch minor problems before they become major. However, if your boiler stops producing hot water, fails to start, makes strange noises, leaks water, or shows error codes, then you will need a boiler repair instead. In some cases, an engineer performing a regular service may discover issues requiring further repair. The best approach is to call a qualified heating engineer who can tell you whether a simple thorough inspection is enough, or if urgent repairs are required to fix a faulty boiler.

Yes, skipping your annual boiler service could affect your warranty. Most manufacturers, including British Gas and other major suppliers, clearly state in their terms that the boiler must be serviced every year by a safe registered engineer. Failure to arrange this annual check could mean that your warranty becomes invalid. This means you would have to cover the full cost of any repairs or replacement parts, even if they would normally have been covered under the warranty. Keeping up with regular servicing is not only a way to ensure your boiler’s safety, but also a way to avoid expensive costs in the long run by maintaining your warranty cover.

Yes. One of the main benefits of regular boiler service is that it allows engineers to identify and resolve minor problems before they develop into costly repairs. For example, replacing a small seal during a comprehensive service can prevent leaks that might otherwise cause major damage to internal boiler parts. Cleaning the pilot light and burner as part of the service can stop ignition issues and ensure the boiler maintains its efficiency. By scheduling an annual boiler service, you reduce the risk of unexpected breakdowns, help keep your warranty intact, and ensure your heating system continues to run smoothly. Over time, this saves money compared to waiting until something breaks and needing a full boiler repair.

For both servicing and repairs, you should always use a Gas Safe registered engineer. For a boiler service, book with a company or individual who can provide a boiler safety checklist and service report to confirm that all safety standards have been met. If you need a boiler repair, you should also use a qualified engineer, especially if you suspect gas leaks or problems with safety devices. Some large companies such as British Gas and local heating firms offer both boiler care plans and one-off repair services. Having a boiler service plan or boiler cover in place is a good idea because it means you will always know who to contact in the event of a faulty boiler.

A boiler service is generally much cheaper than a repair. In the UK in 2025, the average boiler service cost is between £90–£120 for a standard gas boiler. An oil boiler service may cost more, typically £110–£150, because of the extra cleaning required. By contrast, repairs can vary widely depending on the problem. Fixing minor problems such as replacing a thermostat may cost £100–£250, but serious issues such as a broken heat exchanger or pump can easily cost £400–£1,000 or more. This shows why regular servicing is considered an important safety measure and a cost-saving investment. In the long run, paying for yearly servicing helps avoid the much higher cost of emergency boiler repairs.

You should choose a boiler service if your system is working normally but it is due for its annual check. This includes checking safety devices, ensuring your boiler meets safety standards, and keeping efficiency levels high. On the other hand, choose a boiler repair when there is a clear problem, such as no hot water, a faulty boiler that keeps shutting down, or visible gas leaks. A good rule of thumb is to book servicing every 12 months for regular maintenance, and only book repairs when faults appear between those appointments. Having a boiler service plan can make this simpler, as both services and repairs are covered under the same boiler care contract.

A boiler service is planned regular maintenance designed to prevent issues, while a boiler repair is an urgent fix for a problem that already exists. A service involves a thorough inspection of your boiler, cleaning of boiler parts, testing of safety devices, and issuing a service report. It is usually cheaper and takes around 30–60 minutes. A repair, however, involves diagnosing faults, replacing boiler parts, and restoring the system to working order. Repairs may be more expensive and are often carried out as emergency call-outs. In short: a service keeps your boiler efficient and safe; a repair fixes a faulty boiler that is already failing.

Several warning signs suggest you need a boiler repair rather than a service. These include no hot water or heating, frequent resets, banging or whistling noises, visible leaks, and gas leaks. Another red flag is if the pilot light keeps going out or burns with a yellow flame instead of blue, which can indicate incomplete combustion and the risk of carbon monoxide poisoning. Pressure drops, persistent error codes, or warning lights on the display are also signs that you need immediate repair work. If you notice any of these problems, do not wait until your next annual boiler service. Call a qualified heating engineer straight away to make your home a safer place.