Are you wondering what’s included for your annual boiler service costs?

Everyone wants to know where their money is going, and if it’s really going to be worth it. Some of my customers immediately think: “What, £100 a year? What am I really going to get for that?” – the answer is a lot.

Firstly, if your boiler is new, an annual will keep your warranty up-to-date for the full term. Secondly, there are all sorts of other reasons to have your boiler looked at every year – the most important one being to ensure your family is kept safe!

But what will an engineer actually do when they look at your boiler?

As an experienced engineer myself, I know that many of my customers seem to be in the dark about this. That’s why I wanted to write a blog post to help clarify what will actually happen at your boiler service, from the time you book the visit to when you’re handed your certificate.

Why do I need to book a service every year?

I know I’ve already told you it’s important if you want to ensure your property is safe for either your family, or – if you’re a landlord – your tenants, however, let me just highlight this by telling you about a recent visit to a customer’s home.

Their boiler had been fitted 10 years ago, and because they were selling the property, they’d been told to install inspection hatches to allow engineers to inspect the flue and service the boiler. On doing this, the flue did not look right, and seemed disconnected before it went through the roof.

It turned out there had been a roof repair carried out the year before, and the flue had been disjointed during this work. We immediately turned off the appliance, and the customer had no heating or hot water for a week until we sourced parts and a competent roofer to fix the problem.

This client was lucky; exhause fumes were terminating in the attic for 6 – 9 months, directly above a child’s bedroom. This could have been FATAL.

What happens when you book a boiler service?

Whether you book by phone or email, the company you book with should speak to you to confirm a specific date, be it an am or pm appointment. Unfortunately, many engineers can’t guarantee time slot due to traffic and being unable to know exactly how long each job will take.

However, one thing we do offer is what’s known as our ‘first call’ of the day, to help customers out who maybe have to take time off work to be in for a service. You may have to book in advance for this, and if you go for another am or pm slot, you can call on the day to get a better idea of time.

What happens on the day of the service?

Once an engineer arrives at your property, he or she will locate the boiler and ask for the installation and service manual so they can service to the manufacturer’s guidelines.

This is also handy for later, when they need to fill in the log-book and note any adjustments or repairs to be carried out.

Next, the engineer will check your boiler and hot water are working correctly, before carrying out a gas flue analyser test. Depending on the readings (and usually if your boiler is older than two years), the boiler will be stripped, and the heat exchanger, burners and jets cleaned.

All obvious components in the boiler will be checked and tested, as per manufacturer’s instructions. The flue route and integrity will also be checked, and if your boiler is an older open-flued appliance, and flue test and spillage test will also be conducted.

Normally, we also use our visit to check your radiators and thermostats are all working correctly, too.

How long does an average boiler service take?

On average, you’ll find a boiler service usually takes around 30 – 60 minutes, depending on whether the boiler is in its first couple of years, or a bit older. This is because modern boilers don’t need a lot of adjustment within the first two years, as long as the gas analyser readings are okay.

Once boilers get a bit older, they have to be stripped and adjustments made, along with a bit of internal cleaning (as mentioned above) required. This means it takes up to half an hour longer, but is still included in your boiler service costs.

What if something is wrong with my boiler?

Depending on what is wrong with your boiler, an engineer may be able to fix the problem on the spot, or you may require a second visit. This really boils down to time – for you and the engineer.

Engineers try to carry consumable parts in their vans, and usually if it’s as simple as a boiler seal, ignition lead, leaking auto air vents or thermocouples on older boilers, it’s easier to change them during a service. This saves on time and having to book another visit.

However, if it’s found there are more serious issues, or other parts required for your boiler, a second visit would be necessary.

TIP: If you know there’s a fault with your boiler, let the engineer know in advance; don’t just book it in for a service and hope the engineer will fix it. This can often be frustrating for both parties, and it may also increase your boiler service costs.

Will I receive proof my boiler has been serviced?

Once your service is carried out, your chosen engineer will fill in the log book – which is the benchmark book located in the back of the installation manual. They will then fill out your gas safety certificate stating the boiler is fit for use, and mark any known defects.

For landlords, this is much the same, however the certificate is known as a CP12 certificate and has the landlord or letting agent’s details, along with the tenant’s details. This is signed and dated a bit like an MOT certificate, stating on this date the boiler was safe to use.

If you’re a landlord, you have to keep your CP12 for two years.


I hope you’ve found this blog helpful when understanding exactly what will (or at least should!) happen at your boiler’s annual service, and what is included in your boiler service costs (around £100).

Some homeowners seem to think boiler servicing is a cost they can easily do without, and something they can skip. However, thinking like this can be dangerous. Cost shouldn’t matter when it comes to safety; people die every year due to CO poisoning and faulty gas appliances.

Got any questions about your annual boiler service costs? Let me know in the comments’ section, and I’ll reply as soon as I can!