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Annual Boiler Service in the UK: Full Explanation and Costs

Luis Antonio Gómez Pérez
By: Luis Antonio Gómez Pérez
Updated: 9th October 2023

Annual Boiler Service UK
It has been almost a year since you got your brand new highly-efficient boiler, and everything seems to be going well. However, a few months of daily use is all it takes for the efficiency of even the best boiler on the market to start to decline. The picture is undoubtedly worse for old boilers, with some of them working at efficiency levels as low as 60% to 70%!

Every percentage point your boiler's efficiency drops will mean you pay more money to achieve the same result. Imagine that your boiler is 94% efficient, but it drops to 84%. This means that you will waste 16p instead of 6p per every £1 you spend on heating your home.
Although 16p doesn't sound like a lot, when you multiply it by several hours, 7 days a week, and a dozen winter weeks later, you will end up wasting a considerable sum. But let's stop here with the bad news. You can easily tackle this problem before it happens. An annual boiler service is what you need.

Servicing a boiler takes about 30 to 60 minutes and its benefits are worth every pound. Continuing with the previous example, if your boiler’s efficiency has dropped by 10% and the engineer fixes this, you could avoid overpaying around £200* a year on your heating bills.

Gas boiler servicing

By the end of this article, you will know everything about annual boiler servicing: what it involves, how much it costs, how long it takes, and how to get the best deals from local boiler service companies. You will then have the necessary knowledge to compare suppliers in your area objectively.

What is annual boiler servicing?

Annual boiler servicing is a set of checks undertaken by a certified engineer on your central heating system every year. Its purpose is to ensure that your boiler, radiators and other heating appliances continue to run safely and effectively.

Instead of looking at it as a routine procedure, you could think of boiler servicing as a precaution to guarantee that there are no risks of carbon monoxide leaks or other threats. It can prevent potential technical failures that could lead to a boiler breakdown and an unexpected increase in your bills if your heating device’s efficiency decreases too fast.

Why get a boiler service?

These are the benefits of annual boiler servicing:

  • Avoid carbon monoxide leaks and other life-threatening malfunctions
    Carbon monoxide is an odourless and colourless gas which can quickly cause brain damage and, in some cases, death.
  • Save money and keep your heating bills as low as possible
    If your boiler’s efficiency has dropped by 10%, but the engineer fixes the problem, you could avoid overpaying around £2001 a year on your heating bills.
  • Prevent a boiler breakdown and a potential boiler replacement
    If your boiler stops working and you need to replace it, you may pay between £1,000 and £3,000 for a new one, including installation costs.
  • Avoid a hefty emergency repair bill
    Boiler repairs typically cost between £100 and £500, but this could be even more expensive for an emergency call out.
  • Keep your boiler's warranty valid
    Your boiler warranty may be subject to terms and conditions. Usually, the manufacturer’s warranty on your boiler is only valid as long as you fulfil your boiler annual service.

Additionally, if you are a landlord, you are required by law to have your boiler serviced at least every 12 months. You can find out more information about the legal requirements further on in this article.

To take advantages of the benefits of a boiler service, we recommend comparing quotes from local gas safe registered engineers in your area. We can help with that! Simply click the link below to get started.

What happens during boiler servicing?

A typical boiler check includes the following:

Step 1: Visual inspection
The engineer will check that the boiler meets current standards and requirements and look for any signs of damage, corrosion or leaks. They will also visually inspect the flame in your boiler.

Step 2: Removal of the boiler casing
They will check and adjust components as necessary and then clean the inside of the boiler. These checks include the heat exchanger, burner, and other crucial components.

Step 3: Flue check
The engineer will then check the flue pipe (the pipe from your boiler to the outside of your house), ensuring no obstructions and that the flue is well fitted.

Step 4: Operation and control
They will also check that all boiler functions, controls and safety devices are working well.

Step 5: Additional checks
They will check if the boiler has adequate ventilation and that it is far away from combustible materials.

Step 6: Conduct a record
The engineer should make a record of each test. As a homeowner, this information may be helpful for you for future inspections.

Step 7: Boiler fired up
At this point, engineers will check for any operational failures. They will also put back any control they altered during the boiler service to the customer’s settings.

While all of the above should happen during a boiler inspection, it could be the case that engineers follow a different boiler service procedure based on the specific boiler you have. For instance, if you have a condensing boiler, they will also check the boiler's drainage system.

How long does a full boiler service take?

Depending on the brand and model, a boiler service could take between 30 to 60 minutes. However, servicing a boiler could take longer if the engineer comes across a fault.

After the job is done, don't be afraid to ask the engineer any questions you might have regarding the boiler check-up. Engineers will be happy to advise you and explain everything you need to know to keep your boiler running well. Boiler Guide can help you get in touch with the best technicians near you in no time to compare the services they offer.

In terms of when to schedule your yearly boiler service, summer is usually the best time. During this season, you will not use the boiler as much as in the winter. You will also find that engineers aren't as busy at this time of year, which potentially means lower rates.

However, if you think that your boiler may not be working correctly, then the wisest choice is to get in touch with a registered and qualified engineer as soon as possible. There may be a safety issue, and you want this kind of problem solved before it is too late.

Boiler service average duration & cost

Boiler check-up cost

How much a full boiler service costs depends mainly on the type of unit you have and where you live. Servicing a standard-efficiency boiler will cost between £50 and £80, while a high-efficiency condensing boiler service will cost between £80 and £160.

Likewise, boiler services in London are likely to be more expensive than local boiler services in smaller cities or rural areas.

Servicing a boiler during the summer -when engineers aren't as busy- can help you save some money.
These are the main factors that may affect the boiler check total cost:

  • Type of boiler (combi, system or regular)
  • Where you live
  • Boiler fuel
  • Manufacturer and model
  • The boiler location within the house
  • The rates charged by the engineer

If a manufacturer’s warranty no longer covers your boiler, you may consider paying a monthly fee for a boiler cover and service plan. With this option, the cost of your annual service is taken care of; however, over a year, your monthly fees are likely to add up to more than the cost of a boiler service.

Is it worth getting a yearly boiler service?

Yes, it is. Getting your boiler checked at least once a year will keep it safely ticking over and improve your home's overall energy efficiency. As a result, you can have peace of mind that you and your family are safe and save some money on your central heating cost in the long term.

Boiler servicing can also prevent you from spending hundreds of pounds on unexpected boiler repairs or even a couple of thousand on a boiler replacement. It is also necessary to keep your boiler's warranty valid.

Is annual boiler service mandatory?

We have the answer to this question in the infographic below. Just check what situation best applies to you.

Laws on servicing a boiler

Under British law, an annual boiler check by a certified engineer is mandatory for landlords and landladies. However, boiler service is not compulsory in the UK for homeowners who do not rent out their property. The latter, nevertheless, have a duty of care to ensure their appliances are safe and not liable to cause harm.

Find local boiler services

When looking for a boiler service near you, it's essential to check that the engineer is qualified to carry out the work.

Engineers checking on gas boilers must be authorised and regulated by the Gas Safe register, while those servicing oil boilers need the Oil Firing Technical Association (OFTEC) accreditation. Find out what is involved and how much it is likely to cost with our guides to getting a gas boiler service and an oil boiler service.

Comparing quotes is a great way of ensuring you find a best deal on your boiler service, but this can take time. At Boiler Guide, we take care of this by finding you up to 3 offers tailored to your requirements. To get free, no-obligation quotes, simply click the link below.


How often should a boiler be serviced?
You should contact a certified engineer to service a boiler a least once every 12 months. Note that this is an obligation for you if you are a landlord.

The best time to get a yearly boiler service done is in the summer; however, the wisest choice is to get in touch with a registered and qualified engineer whenever you think your boiler may not be working correctly.

Servicing your boiler at least once a year will keep it running safely and efficiently.

Do boilers really need servicing?
Yes, they do. Boilers need regular maintenance to keep your central heating system running reliably, effectively and safely.

Is it worth getting an annual boiler service?
Yes, it is. Booking a domestic boiler service will give you peace of mind that there is no risk of carbon monoxide leaks or other threats and that you and your family are safe. In addition, you can save money on your central heating cost in the long term because the engineer will make sure your boiler is running at its maximum efficiency.

An annual boiler service can also prevent you from spending hundreds of pounds on boiler repairs or even a couple of thousand on a boiler replacement. Furthermore, it is generally necessary to keep your boiler's warranty valid.

By choosing not to have your boiler serviced annually, you’re risking the following:

  • Carbon monoxide leaks
  • A rise in your energy bills
  • A fault that could lead to a boiler breakdown
  • Having to pay an unexpected repair bill

What do they do in a boiler service?
Usually, servicing a boiler follows this procedure:

  • Visual inspection
  • Removal of the boiler casing and adjustment of components
  • Flue check
  • Operation and control
  • Additional checks
  • Conduct a record
  • Boiler fired up

Nevertheless, your engineer may follow a different protocol depending on your specific boiler (e.g. servicing a condensing boiler requires checking the boiler's drainage system).

Who should service a boiler?
A certified and fully-qualified engineer should always be the one who services boilers. A gas boiler service is a job for an engineer authorised and regulated by the Gas Safe register, while an engineer accredited by OFTEC has the required credentials to carry out an oil boiler service.


  1. Energy Saving Trust, Heating your home: Boilers (2022)

Luis Antonio Gómez Pérez

About the author

Luis Antonio Gómez Pérez

Luis Antonio Gómez Pérez is a seasoned Senior Content Writer with international reporting experience. He enriches Boiler Guide with his expertise in sustainability and energy efficiency, as well as with knowledgeable and reader-friendly articles.

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