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28 January 2021

Getting the best boiler service

Find out how you can make sure you get a good boiler service to keep it in tip-top condition.
Boiler engineer 451097
Ellie Simmonds

An annual boiler service is essential for keeping your boiler running smoothly and safely.

Read on to find out what you can do to ensure you get the best boiler service. We'll also tell you how much you should expect to pay for a boiler service so you don't get overcharged.

Jump straight to our reviews of boiler cover companies. Or arrange your boiler service today with a Which? Trusted Trader

Boiler service checklist


Here's what should take place as part of a boiler service:

  • A visual check of the boiler and flame, if possible
  • Checks on the flue (externally and internally)
  • Checking the operating pressure and / or heat input
  • Checking safety devices
  • Check case seals for an effective seal
  • Boiler casing removed to check all main boiler components (burner, heat exchanger, main injector, spark / sensor probe)
  • Boiler fired safely to identify any working faults
  • Boiler parts cleaned, if necessary
  • A service report showing everything the engineer has done

You should get your boiler serviced every year by a Gas Safe registered engineer. You can arrange a service yourself or through a heating engineer – it should cost about £72. Alternatively, you can get boiler cover through a plan, such as Homecare, that includes a boiler service, but this costs more than £200.

We would recommend getting your boiler serviced by a Which? Trusted Trader.

Things to consider and watch out for

Ask what will be included in the boiler service. Watch the engineer and use our checklist to ensure that they cover the basics. A good boiler service should last at least 30 minutes. If it’s shorter than this, ask why. 

Finally, ask for a written report and check it is accurately filled out. If you have any concerns, contact the Gas Safe Register on 0800 408 5500 or at gassaferegister.co.uk. It's also worth getting a carbon monoxide detector.

Although the checklist should stand you in good stead for most boilers, bear in mind that not all boilers are the same.

Most older conventional systems, for example, have parts such as the heat exchanger, burner and fan that would need to be dismantled and checked. This is not normally necessary for a modern boiler, unless the flue gas analysis suggests there's a problem. 

Paying for boiler servicing

Before paying for repairs, check whether your boiler is still under its initial warranty. Most new boilers typically come with cover for parts and labour in the first one or two years.

Some home insurance also gives you cover for boiler breakdowns, either as standard or as an optional extra, so it's worth checking if you already have this. The cost of adding breakdown cover to insurance cover is usually much less than getting a breakdown contract, but you don't get the same benefits.

You'll probably save money if you pay for services and repairs as you go along, rather than take out a boiler servicing contract - where you pay a monthly fee that also covers repairs. Our analysis shows that for more than nine out of ten Which? members this was more expensive than paying for one-offs. 

The majority of Which? members who have a contract say they pay for peace of mind. If this sounds like you, then we'll help you find the best boiler cover policy for you - see our reviews of boiler cover

Boiler servicing results firm by firm


If you opt for ‘central heating response plus’ cover with the AA, you'll be entitled to an annual service per membership period. An engineer will do an initial inspection and service within 42 days of taking out the cover and then you'll be contacted when the second service is due.

The service includes:

  • Boiler combustion test.
  • Visual inspection of flue route and termination.
  • Checking for water leaks, signs of heat stress and mechanical deterioration.
  • Checking pipe work and ventilation.
  • Carrying out a leak detection check.
  • The disassembly and cleaning of key components where they are found to be not performing to the manufacturer’s recommended specification.

The annual service does not include the following:

  • Removal of sludge or hard-water scale from the main heating system.
  • Chemical flush.

Length of service: 30mins

Cost: The AA is no longer providing quotes for boiler and home cover to new customers.

British Gas

British Gas offers a one-off boiler service from around £79 or you can sign up to one of the four HomeCare cover packages which include an annual service. The cost of both will depend on factors such as water hardness and property type.

Once a deal is agreed and you receive a quote your service will include:

  • Making sure the boiler is running safely and efficiently.
  • Testing the flue to make sure your appliance isn't leaking carbon monoxide.
  • Checking the gas pressure to make sure it's right and inspecting your appliance for any wear or leaks.

Neither services cover repairs to your gas boiler.

Length of service: 17mins

Cost: £79.30 for a one-off service or from £222 annual contract


As part of its HomePlan cover, Corgi offers basic boiler and central heating system repairs and an annual boiler service with its 'essentials' cover package . A boiler service is also included in more expensive packages, too. The service includes:

  • A visual check of the boiler.
  • The boiler being fired safely to identify any working faults.
  • A flue gas analysis efficiency test.
  • Opening up the boiler and inspecting it, if necessary.
  • Checking the flue and ventilation are in accordance with Gas Safety (Installation and Use) Regulations.
  • Checking and adjusting the system pressure.
  • Cleaning the condensate trap.
  • Visually checking and bleeding radiators, if necessary.
  • A visual check of the hot water cylinder.
  • Confirmation in writing that the service has been carried out.

If your boiler is over 7 years old when you take out the cover the monthly premium will increase by up to £2.

Length of service: 45mins

Cost: From £156 (£60 excess) or £216 (£0 excess) annual contract


HomeServe offers one-off boiler servicing from around £84. Its service includes:

  • Boiler inspection to make sure it’s working properly.
  • Clean the parts if needed.
  • Check that all the seals and gaskets are secure.
  • Make sure it’s not emitting any unsafe fumes.
  • Test the gas connections and gas pressure.
  • Visually check any other gas appliances.

Appointments are booked in four-hourly windows and can be made via the website. HomeServe doesn’t service or repair Promox, Powermax, Ferroli, Keston or Gledhill boilers.

A service is also included when you sign up to one of its boiler cover packages.

Length of service: 45mins

Cost: £84 for a one-off service or from £258 annual contract

Scottish Power

To receive an annual boiler service with Scottish Power you’ll need to sign up to its boiler and service care' cover which costs from £157.50 per year. Other features in the plan include ongoing maintenance, a 24/7 UK-based helpline and a replacement boiler worth up to £750, if required.

Insurance packages do not include an annual service.

Length of service: 38mins 

Cost: From £157.50 annual contract


For a fixed-price of £90, SSE will send out a Gas Safe registered engineer to service your boiler. If there are repairs needed the engineer can offer you a quote to fix it and you'll be provided with a report at the end.

If anything goes wrong within 21 days of the call-out, an engineer will come out free of charge and if the problem is a result of the service it will also be repaired for free.  

SSE also offer boiler cover that includes an annual service. Prices start from £15 per month. 

Length of service: One hour 

Cost: £90 for a one-off service


The cost and length of an independent boiler service will vary depending on the age and model of your boiler, the area you live, who carries out the service and the time of year, so always seek a handful of quotes and make sure the engineer is Gas Safe registered. 

If your boiler needs a service, visit Which? Trusted Traders to find a reputable trader who has been through our rigorous checks. 

Length of service: Between 25mins and an hour 

Cost: Between £60 and over £100 for a one-off service

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