Gas boiler repairs typically cost £100 to £600. A small part and a quick visit sits near the bottom, and a big component such as a heat exchanger can go past the top. The engineer's time to find the fault is part of the bill, whether or not the first guess turns out to be right.
Repair cost by job size
Typical UK gas boiler repair cost, by job size
| Job size | Typical cost | What it usually looks like |
|---|---|---|
| Small | £100–£200 | Diagnosis and a small part such as a sensor, igniter or seal |
| Typical | £200–£400 | A diverter valve, pump or fan |
| Large | £400–£600+ | A circuit board or heat exchanger, which can exceed the range |
These tiers divide the £100–£600 guide for gas boiler repairs. Repairs are usually done in one to four hours, but if a part has to be ordered you'll pay for a second visit.
What drives the bill
- Call-out terms. Some engineers charge a fee that covers the first visit, others bill by the hour.
- Diagnostic time. A fault code points the engineer in a direction, but it rarely names the failed part.
- The part. Price varies a lot by make and model, and older boilers can be harder to source for.
- Number of faults. One failed component is routine, several at once is a sign the boiler is tired.
- Timing. Emergency or out-of-hours visits cost more than a booked weekday slot.
When a repair stops making sense
If you're being quoted for a major part on an older boiler, set the repair figure against the cost of a new one. A £500 repair on a boiler that is already struggling can be money wasted if another fault follows in the next year. The new gas boiler cost guide shows what a replacement typically costs, and a separate guide on whether to repair or replace an old boiler is planned.
Only let a Gas Safe registered engineer work on a gas appliance, and check their card on the Gas Safe Register site. A regular gas boiler service is the cheapest way to catch a fault early.
Ask whether the call-out fee is credited against the repair and what happens if the part has to be ordered. A diagnostic visit doesn't guarantee a repair is completed that day.
Frequently asked questions
How much does a gas boiler repair cost?
Typically £100 to £600. Small parts are at the bottom, while a heat exchanger or several failed components can exceed the range.
Does a diagnostic visit guarantee a completed repair?
No. The engineer may find the fault but need to order a part, which means a second visit.
Is it worth repairing an old boiler?
It depends on the age, the part needed and the boiler's history. If repairs keep coming, a replacement may be the better use of money.
Are repairs covered by an annual service?
Usually not. A service checks and cleans the boiler, but any repair is charged separately unless you have a separate cover plan.
Ready to talk to a gas boiler replacement specialist?
Get Free Quotes →