Getting the best boiler service

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

Our latest survey found that 9% of gas boilers develop a fault within a year of ownership; 20% within 5 years. Spending on a boiler service could potentially spare you a huge repair cost in the future, by addressing minor faults early on, as well as giving you peace of mind.

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.

Find out more about boiler cover (including why we don't recommend it for most people ) or arrange your boiler service today with a reliable local engineer through Which? Trusted Traders

How much does a boiler service cost?

There are two types of boiler service schemes: 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. It's a little less on average for an electric boiler. If something needs to be fixed, you'll need to pay for that on top. 

In a 2023 boiler customer survey, we found the average repair cost people had paid was £196.

A boiler cover package typically costs £200 to £300 a year. This should include an annual service and cover repair costs. Our survey found that people paid an average of £270 a year for a boiler cover package.

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

Find out how an efficient boiler installation designed by an expert engineer saves you money in the long run. 

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

Our 2023 research found that people with boiler cover paid £270 on average per year, which is 76% more than the average annual cost of servicing and repairs (£153) paid by those who did not have any boiler cover. 

We calculated this by including any costs of repair during the 12 months or £0 if no repairs were needed, and adding an £80 cost to those who had a service in the past year, the average cost of a service at the time of the survey.

An important caveat to these costs is that some boiler cover policies will include more than just service and repairs. For example, they might include cover for drains, plumbing and home electrics. 

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. 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.

Find out what you should expect to pay for a repair in our common boiler problems and repairs guide

Boiler service checklist

The purpose of a service is to prevent your boiler breaking and costing you more in the long run.

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 arrange a service yourself or through a heating engineer – it should cost about £100. Alternatively, you can get boiler cover through a plan, such as Homecare, that includes a boiler service, but this can cost more than £200.

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

Benchmark app

Remembering to get your boiler serviced can be a pain but a new app from Benchmark (available on iOS and Android) will make 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 boilers installation and each service.

The app sends push notifications to alert you when it’s time to get your boiler serviced. All this makes it easy to keep up with regularly servicing your boiler, ensuring it remains in warranty and your heating system performs as efficiently as possible.

Boiler service tips

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 through the Gas Safe Register website.

You should get a carbon monoxide detector to be safe, and you're legally obliged to have one if you live in Scotland.

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.

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. 

If you're getting a replacement boiler, use our new boiler costs guide to see how much you can expect to pay

Boiler servicing customer scores

We also surveyed 10,018 homeowners in May 2023 to gather their opinions about the company they'd used most recently for a boiler service. 

There are scores of independent boiler engineers you could use, but we can't gather a large enough sample size to the able to rate them. The table below shows results for the six most popular boiler servicing companies. 

Most were easy to contact, and easy to schedule a service with, which is reassuring. But there were big differences between the best and worst when it came to value for money: the worst brands may surprise you. 

Boiler servicing information by firm

British Gas

Cost: British Gas offers a one-off boiler service starting from around £99 or you can sign up to one of four HomeCare cover packages, ranging from £200 - £325 a year. 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.

Corgi / OVO Energy

Cost: From £180 to £288 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.

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.

Scottish Power

Cost: annual contracts cost from £48 to £288, 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.

Independents

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 will usually provide better 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.  

Length of service: Between 25 minutes and one hour 

Cost: Between £60 to more than £100 for a one-off service

Boiler servicing information by firm - prices last checked October 2023. Prices ignore introductory offers, so are representative of what you will be paying annually after these offer periods have expired.