Boiler Repair Cost UK: What You'll Pay in 2026
Boiler repairs in the UK typically cost £95–£320 in 2026: diagnosis plus the first hour runs £80–£120 at standard rates, and the common parts — sensors, electrodes, valves, fans, pumps — add £30–£250 on top. Emergency and out-of-hours attendance carries a premium, typically £120–£180 for the first hour. The wide band narrows fast once the fault is named, which is why the diagnosis is the part worth paying a good engineer for.
How repair pricing works
The standard structure: a callout/diagnosis fee covering attendance and the first hour (£80–£120 standard, £120–£180 emergency/out-of-hours), then parts at quoted prices fitted with your approval, plus additional labour if the job runs long. Reputable firms state the rate before dispatch and the parts price before fitting — the invoice should never be the first time you see a number.
Watch for two structures that inflate: 'free callout' models that recover the fee through padded parts and labour, and fixed-price repair menus that price every fault at the worst case. Neither is a scandal; both reward knowing the honest component costs below.
Typical costs by fault
The common repairs, parts and labour combined at standard rates: ignition electrodes and leads £120–£200; thermistors and sensors £110–£180; fans £180–£280; diverter valves £180–£300; pumps £200–£320; printed circuit boards £250–£450 (the repair that most often triggers replacement arithmetic); expansion vessel recharge £90–£140, replacement £180–£300; pressure-relief or filling components £110–£200. Plate heat exchangers (hot water faults on combis) £180–£300; main heat exchangers £400–£600 and usually a replacement conversation instead.
Winter's cheapest 'repairs' cost nothing but knowledge: frozen condensate pipes thawed with warm water, pressure restored via the filling loop, thermostats and meters checked. A decent firm's phone triage walks you through those before dispatching anyone — it's the difference between a £0 fix and a £100 visit to press reset.
Emergency premiums, honestly
Out-of-hours rates are legitimate — engineers on night rotas cost more — but should be declared when you call, not discovered on the invoice. Typical structure: standard rate until early evening, a 1.3–1.5× premium evenings and weekends, more overnight. The honest question a firm should answer on the phone: can this safely wait until morning at the standard rate? No heat with vulnerable residents in freezing weather can't; a noisy-but-running boiler can.
Triage yourself with two facts: does anything work (hot water but no heating means the system limps — usually waitable), and what's the weather doing? Mild-night faults booked for morning save the premium entirely. The exception that overrides all cost logic: any smell of gas means the National Gas Emergency line (0800 111 999) immediately — that call is free and comes before any repair economics.
When repair stops making sense
The working heuristic is the 50% rule: when a repair approaches half the cost of replacement on a boiler past its warranty and past ~10 years, replacement deserves the comparison. The rule sharpens with context — a £300 pump on an otherwise sound 11-year-old boiler is usually worth it; a £450 PCB on a 14-year-old unit with a corroding heat exchanger usually isn't. Repair history matters too: the third significant repair in two winters is a trend, not luck.
Ask the attending engineer for both numbers whenever the question is live — a fair one volunteers them. And run the arithmetic calmly: replacement quoted in a January emergency costs more than the same job quoted in April, which is itself an argument for repairing once more and replacing on your own schedule. Our repair-or-replace guide works the full decision.
| Repair | Typical all-in | Notes |
|---|---|---|
| Diagnosis + first hour (standard) | £80–£120 | Rate stated before dispatch |
| Emergency first hour | £120–£180 | Evenings/weekends/urgent |
| Electrodes / sensors | £110–£200 | Common, quick |
| Fan | £180–£280 | Mid-priced component |
| Diverter valve / pump | £180–£320 | Frequent on older combis |
| PCB | £250–£450 | Often triggers replace arithmetic |
| Plate heat exchanger | £180–£300 | Hot-water faults on combis |
Reading quotes against these numbers
National price bands earn their keep at comparison time: any quote inside the range with clear line items is negotiating in good faith; anything dramatically outside it — in either direction — is a prompt for questions rather than automatic rejection. Regional variation is real (London and the South East price higher throughout), as is system condition, which legitimately moves installation prices. What never varies legitimately: doorstep supplements and prices that grow after work has started.
Frequently asked questions
How much does a boiler engineer charge per hour?
Standard rates run £60–£100/hour with the first hour often bundled into a £80–£120 callout/diagnosis fee; out-of-hours multiplies by roughly 1.3–1.5×. The rate should be stated before anyone travels.
Why did diagnosis cost money when nothing was fixed?
Diagnosis is the skilled part — identifying the fault is what the first-hour fee buys, and it's owed whether you proceed with the repair or take the finding elsewhere. What it should never be is a surprise: the fee belongs in the booking call.
Are boiler parts marked up?
Typically yes, modestly — trade price plus a handling margin is normal and fair. You're entitled to see parts itemised on the invoice, and dramatic markups on cheap components are the thing itemisation exists to expose.
Is it cheaper to use the boiler manufacturer's repair service?
Rarely for out-of-warranty work — manufacturer services price at premium fixed rates. In warranty, though, use the manufacturer route where the fault is covered; independent work on a warrantied fault can complicate claims.
Getting this sorted properly
If reading this has confirmed you need an engineer rather than an afternoon, that's a useful outcome — the expensive version of most heating faults is the one that was almost fixed. The Gas Safe registered engineers in our network do this work daily: they carry the common parts for the mainstream brands, price before starting, and tell you honestly when a repair stops making financial sense on an ageing boiler. Breakdowns get priority response; planned work gets a proper fixed quote after a survey.
Carbon monoxide is odourless and colourless. Our CO safety guide covers the symptoms, where alarms belong and the emergency response.