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A boiler repair in London costs £150 to £400 for most faults: the call-out and diagnosis is £60 to £125, labour £80 to £140 an hour, and the common parts run from £120 for a pressure fault to £300 for a fan and £450 for a circuit board. An annual service is £80 to £150, a landlord gas safety certificate £50 to £120.
| Job | London low | London typical | London high | UK typical | What moves the price |
|---|---|---|---|---|---|
| Call-out and diagnosis, weekday | £60 | £120 | £125 | £80 | Often waived if you go ahead with the repair |
| Labour, per hour | £80 | £110 | £140 | £70 | Out of hours £140 and up |
| Pressure loss, expansion vessel or valve | £120 | £200 | £280 | The most common winter fault | |
| Fan | £200 | £300 | £420 | £275 | |
| Diverter valve | £150 | £280 | £390 | Heating works but no hot water, or the reverse | |
| Pump | £180 | £300 | £420 | ||
| Circuit board (PCB) | £290 | £450 | £650 | £350 | Parts vary by brand; imported parts about 15 per cent dearer than in 2024 |
| Heat exchanger | £450 | £650 | £880 | £425 | On a boiler over 12 years old, the point where replacement wins |
| Annual service | £80 | £95 | £150 | £100 | Book in September or early October; November to January is the rush |
| Landlord gas safety certificate (CP12) | £50 | £80 | £120 | £75 | Plus £10 to £20 per extra gas appliance |
| Service and CP12 in one visit | £85 | £150 | £180 | £135 | Cheaper than two visits |
A repair visit starts with diagnosis: the engineer reads the fault code, tests the component and quotes the part before fitting it, and most London firms waive the call-out fee if you go ahead. The cheap fixes are pressure and valves; fans, pumps and diverter valves sit in the middle; the circuit board and the heat exchanger are the expensive two, and on a boiler past 12 to 15 years a heat exchanger quote is usually the moment to price a replacement instead.
An annual service is different work: a check of the burner, heat exchanger, seals, flue and gas pressure, and it is what keeps the manufacturer's warranty valid, so a 12-month gap can void it. If you let the property, the law adds a gas safety check every year by a Gas Safe engineer, with a copy of the certificate to tenants within 28 days; the check can be done up to two months early without losing the anniversary date.
Only a Gas Safe registered engineer may work on a gas boiler. Check the number on their card by texting Gas and the number to 85080. London has 3.2 registered engineers per thousand households, and the hard water scales heat exchangers faster than elsewhere.
Prices last checked: September 2026. Based on the published 2026 repair and service prices of five London heating firms, MyJobQuote's 2026 guide and Checkatrade's repair snippets. PROS AI does not yet have enough completed boiler repairs in London to publish its own averages.
£150 to £400 for most faults, including the part. The visit itself is £60 to £125 and labour £80 to £140 an hour; a pressure or valve fault is £120 to £280, a fan £200 to £420, a pump £180 to £420, a circuit board £290 to £650 and a heat exchanger £450 to £880.
For a fan, a pump or a valve, yes: £200 to £400 buys another few winters. For a circuit board or a heat exchanger, usually not: £450 to £880 into a boiler at the end of its life, when a like-for-like combi swap is £2,200 to £3,500 with a 7 to 10 year warranty and lower gas bills.
£80 to £150, with most firms at £95 to £120. The engineer checks the burner and heat exchanger, seals, flue and combustion, gas pressure and safety devices, and cleans what needs cleaning. A service does not include a gas safety certificate or an electrical certificate; ask for the CP12 at the same time if you let the property.
£50 to £120 for the boiler and one other appliance, plus £10 to £20 per extra appliance. The law requires it every 12 months, a copy to existing tenants within 28 days and to new tenants before they move in, and the record kept for two years. Booking it with the annual service costs £85 to £180 for both.
Yes, and it is the cheapest way: £85 to £180 for both against £95 plus £80 booked separately. A quarter of inner-London homes have no mains gas; those need an electrical safety report (EICR) instead, not a CP12.
Written by Shay Hazan, PROS AI.
£90 - £600per job
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