How much is a boiler service

Whether you’re recovering from your morning shower or tuning the thermostat on a rainy evening, chances are your boiler is silently doing its job in the background—until something goes wrong. Boiler breakdowns often strike at the worst possible time, usually in winter’s chill, causing both discomfort and unexpected repair bills. So, what can you do? One of the simplest yet most overlooked answers is a regular boiler service. But how much is a boiler service, exactly?

This article dissects the costs across boiler types, locations, and service providers. We’ll also explain what a service actually involves, whether one-off checks are more economical than subscription plans, and when servicing becomes mandatory. You’ll get the clarity you need to budget smartly and ensure your boiler stays efficient, safe, and reliable.

What’s Included in a Boiler Service

boiler service isn’t just a quick checkup — it’s a thorough inspection that ensures your heating system is running safely, efficiently, and in line with current regulations. When carried out by a qualified professional (usually a Gas Safe registered engineer), the service will involve multiple steps, all designed to prevent problems before they arise.

Here’s what’s typically included in a standard boiler service:

1. Visual Inspection

The engineer starts with a visual check of the boiler and surrounding area. They look for any signs of leaks, corrosion, or damage. This also includes assessing the flame (in older boilers), ensuring that it’s burning correctly and is the right colour — typically blue.

2. Testing Boiler Controls and Thermostats

To make sure your boiler is functioning properly, the technician will check all key controls and safety devices. These include:

Room thermostat and timer/programmer
Boiler pressure and temperature controls
Safety shut-off mechanisms

This step confirms that your system is heating properly and that all controls respond correctly.

3. Internal Component Inspection and Cleaning

After the initial checks, the engineer will remove the boiler’s casing to access its inner components. Key parts they examine and clean (if needed) include:

Heat exchanger
Burner
Main injector
Spark probe and sensors

Cleaning prevents build-up of soot and debris, which can affect performance or pose a safety hazard over time.

4. Flue and Ventilation Check

The flue (the pipe that expels gases outside) must be free from blockages and installed correctly. The engineer will also ensure there’s adequate ventilation around the boiler to prevent dangerous carbon monoxide build-up.

5. Gas Pressure and Flow Tests

The engineer will measure gas pressure to make sure the boiler is receiving the correct fuel flow for optimal combustion. Low pressure may indicate a leak or valve issue.

6. Combustion Analysis (for modern boilers)

Using a flue gas analyser, the technician can check how efficiently the boiler is burning fuel. Poor combustion can lead to dangerous levels of carbon monoxide.

7. Safety Certification and Reporting

At the end of the service, the engineer will provide a full service record. For landlords, this includes a CP12 Gas Safety Certificate, a legal requirement when renting out a property. Even homeowners should keep this documentation in case of warranty claims or insurance purposes.