Getting the best boiler service

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

Spending on a boiler service could potentially spare you huge repair costs in the future, by addressing minor faults early on, as well as giving you peace of mind.

Here's how to ensure you get the best boiler service, including how much you should expect to pay and which companies boiler owners recommend to carry out the job.

Find out what you should expect to pay for repairs in our guide to common boiler problems. Or, if you're thinking of getting a new boiler, head to the best boiler brands.

How much does a boiler service cost?

There are two types of boiler service scheme: an annual boiler cover package or a one-off service.

A one-off service should cost somewhere from £70 to £110 for a gas boiler. The average is around £76. It's a little less on average for an electric boiler. 

If something needs to be fixed, you'll need to pay for the repair on top. 

In our May 2024 survey of boiler customers, we found the average cost people had paid for a one-off repair following a boiler service was £181.

Our survey found that people paid an average of £177 a year for a boiler cover package, though some can be as much as £300 a year. This premium should include an annual service and cover any subsequent repair costs. 

Some boiler cover packages have a cheap introductory offer but prices ramp up from the second year. 

Why paying for a one-off service is usually better than boiler cover

An annual service costs on average £76, so it’s a relatively small outlay per year to ensure your boiler is running efficiently. If your boiler is still under its manufacturer's warranty, not getting it serviced every year might invalidate its protection policy.

If your boiler is in good shape, then paying as you go is likely to be more cost-effective than paying hundreds of pounds a year for a boiler cover policy that you rarely, or never, actually need.

Boiler cover policies usually come with a hefty monthly or yearly premium. It’s uncommon for boilers to need frequent enough repairs for these policies to be cost effective over any length of time. It's also common for prices to spiral with increasing premiums every year. 

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

Our longstanding view is that stand-alone boiler cover isn't usually worth it. Read more about the costs in our guide to boiler cover.

The best boiler service companies

 In May 2024, we surveyed 10,028 homeowners to gather their opinions about the company they'd used most recently for a boiler service. 

The table below shows results for fifteen boiler servicing companies, alongside an aggregated score from those who had used an independent local trader. 

Log in or join Which? to unlock our table and find out which boiler servicing companies customers rate best for ease of contacting, value for money and more.

Get more details on the biggest companies in our boiler servicing information by firm.

Boiler service checklist

The purpose of a service is to prevent your boiler breaking and costing you more in the long run. It's a good idea to be present when yours is taking place and ask your engineer to explain what they've done and why.

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

• A visual check of the boiler and flame.
• 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 check an engineer's credentials through the Gas Safe Register's website.

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. 

You can search for vetted and approved heating engineers with the correct certifications through Which? Trusted Traders.

Boiler service tips

Ask what will be included in the boiler service before they begin. Watch the engineer and use our checklist to ensure that they cover the basics. A good boiler service should last at least 30 minutes.

Before they leave, make sure they provide you with a written report and check it is accurately filled out. 

While your engineer is in your home, it's a good opportunity to ask for help with getting your boiler set up to operate as efficiently as possible. Let them know what temperature you like your home and hot water to be at and how important cost efficiency is to you. They may be able to set up your flow temperature at a lower level to save you money, or make other adjustments to improve your winter energy bills. 

If there's something wrong with your boiler, a service should hopefully identify the problem early on. If your engineer tells you they need to make a repair, 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.

You can find out how much you might need to pay in our guide to common boiler problems and repair costs.

Need a replacement boiler instead? Check our guide to how to buy the best boiler.

Boiler servicing information by firm

British Gas

Cost: British Gas offers a one-off boiler service starting from around £93 or you can sign up to one of three HomeCare cover packages, ranging from £21 to £27 a month. 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:

• Checking your boiler for corrosion and leaks
• Cleaning its parts as required
• Removing your boiler casing to check its main components are working
• Putting the casing back on and make sure it’s properly sealed
• Checking the gas pressure to make sure it’s at the right level
• Doing a flue test to check that there are no unsafe emissions coming from your boiler

At the end of the visit, their engineer will leave a checklist with you including all the relevant safety information for your boiler. Neither services cover repairs to your gas boiler.

Visit the British Gas website for more information.

Corgi / OVO Energy

Cost: From £180 with a £60 excess.*

• 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 seven years old when you take out the cover, the monthly premium will increase by up to £2.

Visit the Corgi website for more information.

HomeServe

Cost: £108 for a one-off service or from £108 (£100 excess, increasing to £275.52 in second year) to £216 (£60 excess, increasing to £659.52 in second year) for an annual contract.*

• Boiler inspection to make sure it’s working properly
• Cleaning the parts if needed
• Checking that all the seals and gaskets are secure
• Making sure it’s not emitting any unsafe fumes
• Testing the gas connections and gas pressure
• Visually checking 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 free service is also included in the first year when you sign up to one of its boiler cover packages.

Visit the HomeServe website for more information.

Scottish Power

Cost: annual contracts cost from £14 a month to £24.50, with a £99 excess fee.*

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

The 'Boiler Insurance' packages do not include an annual service.

Visit the Scottish Power website for more information.

Independent boiler engineers

Cost: Between £60 to more than £100 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 in which 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. 

A small business should provide good service to customers, especially locally, as they rely on word of mouth and recommendations to retain and grow their business. 

A potential issue is that independent traders are often very busy, so may not be able to respond as quickly as big companies. However, most will have several trusted colleagues that they can recommend if they are too busy or are on holiday.

When searching for a gas engineer, you should be looking for somebody that you feel confident with and can call back on a regular basis,. This will build up a trusting relationship for valuable advice. A good local gas engineer should be happy to discuss issues on the phone, whereas a large company is likely to charge for a visit.

Over time, your engineer will become familiar with your boiler, which helps to pre-empt issues before they become major problems.  

*Prices last checked October 2024. Prices ignore introductory offers, so are representative of what you will be paying annually after these offer periods have expired.

Use the Benchmark boiler servicing app

A new app from Benchmark (available on iOS and Android) makes boiler servicing more transparent and easier for homeowners to stay on top of.

Like a car’s service booklet, the Benchmark app acts as a digital record of your boiler’s installation and servicing history.

If your boiler has been installed within the past 12 months and a Digital Benchmark record was created by your installer, it will let you see exactly what has been done during your boiler's installation and each service.

The app sends push notifications to alert you when it’s time to get your boiler serviced.

Time to replace your boiler? Read up on the best heating systems for your home and see our customer and engineer reviews of the best gas and oil boiler brands.