The Short Answer
On our estimates, most boiler repairs cost £100 to £900 including parts. A fix that needs no parts, or a cheap one, is about £90 to £250; replacing a sensor, valve, thermostat or fan is £200 to £450; a new circuit board or heat exchanger is £400 to £900.
Engineers charge about £50 to £80 an hour plus parts, and an emergency or out-of-hours repair costs £230 to £680. If the pressure has dropped, you may be able to fix it yourself before you call anyone.
Boiler repair prices by fault
| Repair | Typical cost, parts included |
|---|---|
| No parts, or a cheap part (reset, adjustment, pressure) | £90 to £250 |
| Sensor, electrodes, thermostat, valve or fan | £200 to £450 |
| Printed circuit board (PCB) or heat exchanger | £400 to £900 |
| Emergency or out-of-hours repair | £230 to £680 |
| Gas Safe engineer, per hour (parts extra) | £50 to £80 |
Fixed price or by the hour?
There are two ways you'll be charged:
- By the hour, plus parts: about £50 to £80 an hour on our estimates. Ask what the first hour or call-out costs, and whether finding the fault is included.
- A fixed price. Some national firms sell a fixed visit: BOXT charges a set fee to diagnose and fix anything that needs no parts, with a fixed price for each part on top, and you pay after the job's signed off. When we checked in October 2026, British Gas's one-off repair was £295, parts and labour included, with no fee if it can't be fixed and a 12-month guarantee on the work (some faults excluded).
Whichever you choose, I'd get the price for the part and the labour agreed before the engineer starts the repair.
Two things to try before you call
Low pressure. Worcester Bosch, the boiler maker, says topping up the pressure is a simple fix you can do without an engineer: use the filling loop to bring the gauge up to about 1 bar, following your boiler's manual. If the pressure keeps dropping, I'd call an engineer rather than keep topping it up.
A frozen condensate pipe in a cold snap. It's normally a plastic pipe that runs from the boiler to a drain. Worcester's advice is to pour warm (not boiling) water along it if you can reach it safely, then reset the boiler.
Warning signs and gas emergencies
Gas Safe Register lists the signs that a gas appliance isn't working safely: a floppy yellow flame, black or brown marks on or around it, a pilot light that keeps going out, and more condensation than usual in the room. Stop using it and get it checked.
If you smell gas: open doors and windows, turn the gas off at the meter (unless it's in a cellar or basement), don't use naked flames or electrical switches, and call the National Gas Emergency number, 0800 111 999 (0800 002 001 in Northern Ireland). Any repair to a gas boiler must then be done by a Gas Safe registered engineer.
Boiler cover
Cover plans cost about £8 to £30 a month. When we checked in October 2026, British Gas's repair-and-cover plan was £30.25 a month with a £60 excess on each future repair. Before you sign up, I'd add up a year's payments and compare them with the repair prices above, and read the exclusions and the excess before you sign.
Repair or replace?
Boilers last around 10 to 15 years. I'd fix a cheap part on a boiler of any age. But if a boiler past ten years old needs a circuit board or heat exchanger, at £400 to £900, I'd put that money towards a new boiler instead. Gas Safe Register recommends a service every year unless the maker says otherwise, which catches small faults early: see boiler service costs.
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Frequently asked questions
How much does it cost to fix a boiler?
On our estimates, most repairs cost £100 to £900 including parts: about £90 to £250 with no parts, £200 to £450 for a part such as a sensor or fan, and £400 to £900 for a circuit board or heat exchanger.
What are the signs of boiler failure?
Gas Safe Register's warning signs are a floppy yellow flame, black or brown marks around the appliance, a pilot light that keeps going out and more condensation than usual.
How much is a call-out charge for a boiler engineer?
Engineers charge about £50 to £80 an hour plus parts on our estimates; emergency and out-of-hours repairs cost £230 to £680. Ask whether the first hour and diagnosis are included.
Should a boiler be serviced every 12 months?
Gas Safe Register recommends a yearly service for every gas appliance unless the manufacturer says otherwise. Baxi and Glow-worm both make a yearly service a condition of their warranties.
Can I repressurise my boiler myself?
Yes, Worcester Bosch says topping up is a simple fix: use the filling loop to bring the gauge to about 1 bar. If it keeps dropping, call an engineer.
How we priced thisView sources (10, 3 official)
Rules come from the legislation and official guidance, read at source. Prices are our estimates: we check them against trade price data, retailer shelf prices and specialists' price lists, then build them up from their parts so the totals add up. Below are the sources behind the page; the trade price guides we only compare against aren’t listed. Where sources disagreed, we've said so. More on our method.
- OfficialThe Gas Safety (Installation and Use) Regulations 1998, regulation 3, legislation.gov.uk. Checked 15 Oct 2026.
- OfficialSafety check your gas appliances, Gas Safe Register. Checked 15 Oct 2026.
- OfficialWhat to do in a gas emergency, Gas Safe Register. Checked 15 Oct 2026.
- IndustryWhat to do if your boiler loses pressure, Worcester Bosch. Checked 15 Oct 2026.
- IndustryHow to thaw a frozen boiler condensate pipe, Worcester Bosch. Checked 15 Oct 2026.
- IndustryBoiler repair, BOXT. Checked 16 Oct 2026.
- IndustryBoiler repair, British Gas. Checked 16 Oct 2026.
- IndustryHow much does a new boiler cost?, E.ON Next. Checked 16 Oct 2026.
- IndustryHow long does a boiler service take and how much does it cost?, Baxi. Checked 16 Oct 2026.
- IndustryHow much does a boiler service cost?, Glow-worm. Checked 16 Oct 2026.
