How often should I get my boiler serviced?
The short answer
Once a year. Gas Safe Register and boiler manufacturers recommend an annual service by a Gas Safe registered engineer, and most boiler warranties require it. A gas boiler service typically costs £80 to £120, with an average of about £100.
Key points
- Service your boiler every 12 months, ideally in late summer or early autumn before the winter rush.
- Most manufacturer warranties are only valid if the boiler is serviced every year.
- A proper service includes a flue gas analyser test and an entry in the boiler log book.
- Homeowners are not legally required to service a boiler. Landlords must have an annual gas safety check.
Why once a year
A boiler burns gas in a sealed chamber and sends the fumes out through a flue. Over a year, burners can clog, seals can perish and flues can become blocked or damaged. An annual service catches these problems before they cause a breakdown or, worse, a carbon monoxide leak.
There is also a money reason. Nearly every boiler manufacturer makes an annual service a condition of the warranty. Miss one and a repair that would have been free could cost hundreds of pounds.
What a proper service includes
A service is more than a quick look. A Gas Safe registered engineer should:
- Check the boiler and its controls are working correctly.
- Check for gas leaks and confirm the gas pressure and flow are right.
- Run a flue gas analyser test to measure what is coming out of the flue.
- Inspect the flue and its terminal outside, and check there is enough ventilation.
- Clean or replace parts as needed, and check the system pressure.
- Fill in the boiler log book or service record, and leave you a service sheet.
If the engineer is in and out in 15 minutes with no analyser and no paperwork, you have not had a proper service. Always check they are on the Gas Safe Register first.
What it costs in Glasgow
| Boiler type | Typical range | Average |
|---|---|---|
| Gas boiler | £80 to £120 | £100 |
| Oil boiler | £75 to £110 | £92.50 |
| Electric combi | £70 to £110 | £90 |
Many Glasgow firms offer annual service plans that spread the cost and include priority callouts. Compare the plan price with a one-off service plus your likely repair costs before signing up.
Service versus gas safety check
They are different jobs. A service keeps the boiler running well. A gas safety check confirms every gas appliance in the home is safe, and produces a record that landlords must have each year by law.
Landlords can usually book both on the same visit and save money. Our guide to landlord gas safety certificate costs in Glasgow explains the rules.
Warning signs you should not wait for
Book an engineer straight away, whatever the date of your last service, if you notice:
- A lazy yellow or orange flame instead of a crisp blue one.
- Black marks or soot around the boiler.
- A pilot light that keeps going out, or a boiler that keeps locking out.
- Condensation on nearby windows or a musty smell.
- Your carbon monoxide alarm sounding. Get everyone outside and call 0800 111 999.
Every home with a boiler needs a carbon monoxide alarm. See our Scottish alarm rules guide.
Questions
Is a boiler service a legal requirement?
Not for homeowners. It is strongly recommended and usually required by your warranty. Landlords must have an annual gas safety check, which is a legal requirement.
How long does a boiler service take?
Usually 30 to 60 minutes for a standard gas boiler, longer if parts need cleaning or replacing.
Can I service my boiler every two years?
You can, but you risk invalidating the warranty and missing faults. The standard advice from Gas Safe Register and manufacturers is every year.
What is the best time of year for a service?
Late summer or early autumn. Engineers are busier from October onwards, and you want problems found before you need the heating every day.
Sources
- Checkatrade: boiler service cost guide (opens in a new tab)
- Gas Safe Register (opens in a new tab)
- mygov.scot: fire and smoke alarms (opens in a new tab)
This guide is general information about Glasgow and Scotland, checked on 3 November 2026. Prices and rules change, so confirm anything important with the organisation named before you act.
