Most UK boiler repairs cost somewhere between £100 and £750, with the average sitting around £300, though the exact figure depends heavily on which part has failed.
A simple pressure or thermostat fix sits at the cheaper end; a heat exchanger or control board replacement sits at the expensive end.
This guide breaks down typical costs by fault and part, explains what makes up the bill, and covers when a repair stops making financial sense compared with replacing the boiler.
Boiler repair costs by fault and part
| Fault or part | Typical UK cost |
|---|---|
| Low pressure / pressure sensor | £100–£250 (part alone often £15–£30) |
| Thermostat fault or replacement | £100–£250 |
| Diverter or other valve replacement | £100–£250 |
| Frozen or blocked condensate pipe | £100–£200 |
| Pump replacement | £250–£400 |
| PCB (control board) repair or replacement | £250–£400 (part alone can run to several hundred pounds) |
| Heat exchanger replacement | £400–£750+ |
| Emergency/out-of-hours repair (any fault) | £225–£675, average around £450 |
These are typical ranges rather than fixed prices. Your actual bill depends on your boiler’s make and age, your location, and whether the engineer needs to source a specific part.
What makes up the bill
A repair invoice is generally made up of three things:
- A callout fee, which covers the engineer’s travel and the initial diagnostic visit. Independent Gas Safe engineers typically charge around £60–£100 for this; some fold it into a fixed repair price instead.
- Labour, generally billed at an hourly rate of roughly £50–£80 for a Gas Safe registered engineer.
- Parts, which range from a few pounds for a small component like a washer to several hundred pounds for a printed circuit board or fan.
Emergency or out-of-hours callouts typically cost more than a scheduled daytime visit, which is one reason it’s worth booking a non-urgent repair in advance where you safely can rather than waiting until it becomes an emergency.
Repair or replace?
Three questions, asked in order, cover most real-world cases:
- Is the boiler under 7 years old, or still under warranty? If yes, repair. It’s very likely the cheaper option and the boiler has plenty of working life left.
- If not, has it needed 2 or more repairs in the past 12 months? If yes, replace. A pattern of repeated faults usually points to a boiler nearing the end of its working life rather than one bad part.
- If not, is this repair likely to cost more than roughly half the price of a full replacement? If yes, replace. Below that threshold, repair is generally still the more cost-effective choice.
There’s no single fixed rule here, this is a practical rule of thumb rather than a figure from a specific source, but it reflects the same factors most engineers weigh up: age, fault frequency, and cost relative to starting fresh.
A full UK boiler replacement, including installation, typically costs in the region of a few thousand pounds, varying by boiler type and installation complexity.
It’s also worth factoring in efficiency: a newer A-rated condensing boiler can reduce energy bills compared with an older, less efficient model, which offsets some of the replacement cost over time.
How to reduce your repair costs
An annual boiler service, which typically costs between £80 and £120, is one of the most effective ways to catch developing faults early, before they turn into a more expensive repair.
It’s also usually a condition of keeping a manufacturer’s warranty valid, so skipping it can be a false economy even before you factor in repair risk.
If you’re a tenant or landlord: who pays?
In a rented property, the landlord is responsible for repairing and maintaining the heating installation, not the tenant.
Under Section 11 of the Landlord and Tenant Act 1985, landlords in England and Wales must keep the installations for space heating and water heating in proper working order, which includes the cost of repairs. Tenants shouldn’t be asked to cover the cost of a boiler repair caused by normal wear and tear.
(Different rules on repair timescales and enforcement can apply in Scotland and Northern Ireland. This section reflects the position in England and Wales.)
Frequently asked questions
Around £300, with most repairs falling between £120 and £750 depending on the fault.
Usually, yes, for a single fault. But if the repair is expensive relative to a full replacement, or your boiler is older and failing repeatedly, replacement can work out cheaper over time.
Often, yes. A callout fee typically covers the engineer’s time and diagnosis regardless of outcome, unless you’ve agreed a fixed no-fix-no-fee arrangement in advance.
Not entirely, but an annual service significantly reduces the risk of an expensive breakdown by catching minor issues early.
Sources
- Checkatrade, Boiler Repair Costs cost guide (https://www.checkatrade.com/blog/cost-guides/boiler-repair-costs/)
- Energy Saving Trust, Boiler services explained (https://energysavingtrust.org.uk/boiler-service-explained/)
- Landlord and Tenant Act 1985, Section 11, legislation.gov.uk (https://www.legislation.gov.uk/ukpga/1985/70/section/11) — approved source
- Shelter England, Heating, hot water and power problems (https://england.shelter.org.uk/professional_resources/legal/housing_conditions/responsibility_for_repairs/heating_hot_water_and_power_problems) — approved source
Accurate as of: 10 August 2026