Boiler Service Cost UK 2026: Flat £85 | CAF Heating

The typical boiler service cost in the UK is £70 to £120 for a standard gas boiler, depending on where you live and who you book. At CAF Heating we charge a flat £85 across Surrey and South London - no call-out charge, no VAT on top, and the same price whichever of our towns you're in.

The headline number does not say much on its own. What matters is what the engineer does for the money, what's quietly left out of a cheap quote, and what it costs you if you skip the service altogether. We've been servicing boilers across Surrey and South London since 1996, so here's the honest breakdown - including our own pricing next to typical UK ranges so you can compare like for like.

Boiler service prices in 2026: what you should expect to pay

Prices vary by boiler type and by how you buy - a one-off visit, a bundle with a landlord certificate, or an annual agreement. The table below shows typical UK ranges alongside what we charge. Our prices are flat and fixed: the price we quote is the price you pay, and because we're not VAT registered there's no 20% added at the end.

A quick note on back boilers: these older units sit behind a fireplace and take longer to open up, inspect and reseal, which is why they cost more everywhere. If you've got one, tell us when you book and we'll confirm a fixed price before anyone comes out - no surprises on the day.

For landlords, the service + CP12 bundle is usually the smart buy. You need the landlord gas safety certificate by law every 12 months anyway, and having both done in one visit saves £15 against booking them separately with us - and considerably more against booking them separately with two different firms.

What's included in a proper boiler service

This is where cheap quotes and thorough services part company. A proper annual service is a measured inspection against the manufacturer's specification, not a quick visual once-over. When we carry out a boiler service, the engineer works through the full checklist:

• ◆Flue gas analysis - a probe in the flue measures the combustion readings, which tell us whether the boiler is burning gas safely and efficiently. This is the single most important test of the visit
• ◆Heat exchanger inspection - checking for debris, corrosion and blockages that quietly drag efficiency down and eventually cause breakdowns
• ◆Seals and gaskets - checking the case seals and burner door seal, because a failed seal can let combustion products escape into the room
• ◆Magnetic filter clean - if you have one fitted, we open it, clean out the captured sludge and refit it so it keeps protecting the boiler
• ◆Gas pressure and flow checks - confirming the boiler is getting the gas rate the manufacturer specifies
• ◆Flue and ventilation check - making sure the flue is routed, supported and terminating correctly
• ◆Controls and safety devices - testing that the thermostat, timer and safety cut-outs all do their job
• ◆A written record - the dated service record that keeps your manufacturer warranty valid

If you want the full detail on each of those checks and why they matter, we've written a complete guide to what a boiler service includes. The short version: if an engineer is in and out in 20 minutes and never connected a flue gas analyser, you didn't get a service - you got a glance.

What a boiler service doesn't include

A standard annual service covers inspection, testing and cleaning - it doesn't cover repairs. If the service uncovers a fault, the engineer will explain what's wrong, what the fix costs, and whether it's urgent or can wait. Specifically, a service does not include:

• ◆Replacement parts - if a component has failed or is on its way out, parts and the labour to fit them are quoted separately
• ◆A power flush or chemical clean of the radiator system - that's a separate job for sludged-up systems
• ◆Repairs to pipework, radiators or cylinders elsewhere in the house
• ◆A landlord CP12 certificate - that's a legally distinct inspection, though we bundle the two together for £155

Any decent firm will tell you the repair price before doing the work, not after. That's how we operate: you get a fixed written figure, and nothing happens until you say yes.

Why boiler servicing prices vary so much

Ring three firms and you can get three quotes anywhere from £60 to £150 for what sounds like the same job. There are usually four things driving the difference:

• ◆Location - London postcodes carry a premium, often £20 to £40 above the national average, driven by travel time, parking and higher overheads. Surrey sits just below that, which is partly why our flat £85 undercuts most London quotes
• ◆Boiler type - combis and system boilers are the standard price; back boilers, older floor-standing units and LPG appliances take longer and cost more
• ◆One-off vs contract - a monthly care plan spreads the cost and adds breakdown cover, but over a year you'll often pay £200 to £350 for cover you may never use. Our £240 Service Agreement includes the annual service, a CP12 and priority call-out, so you can see exactly what the extra £155 over a one-off service buys
• ◆What's actually being done - the cheapest quotes are sometimes a visual check with no flue gas analysis. If a price looks too good, ask exactly which tests are included before you book

One more thing to check regardless of price: the engineer must be on the Gas Safe Register - it's illegal for anyone else to work on a gas boiler in the UK. Ask to see the ID card, and check the back of it shows they're qualified for boiler work. Every CAF engineer carries one, and we'll happily show it at the door.

Skipping the annual service can void your boiler warranty

Nearly every boiler manufacturer - Vaillant, Worcester Bosch, Ideal and the rest - makes an annual service by a Gas Safe registered engineer a condition of the warranty. Miss a year, and the manufacturer is within its rights to refuse a claim, even if your boiler is only two years into a ten-year guarantee.

In practice that means an £85 service you skipped can turn a free warranty repair into a bill of £300 to £600 - and if the heat exchanger fails, considerably more. As a Vaillant Approved Installer, we register our Vaillant installations for the 10-year parts and labour warranty, and we make a point of telling every customer the same thing: that warranty is only as good as your service record. Keep the paperwork from each visit; it's your proof if you ever need to claim.

There's a safety case too, not just a financial one. The Health and Safety Executive recommends gas appliances are checked regularly by a Gas Safe registered engineer, because poorly maintained boilers are a leading cause of carbon monoxide incidents in the home. An annual service is how a slow-developing fault gets caught before it becomes dangerous.

The best time of year to book a boiler service

Summer, comfortably. Between May and September demand drops, appointment slots are plentiful, and if the service does turn up a fault you have months to fix it before you actually need the heating. We've covered the full reasoning in our guide to servicing your boiler in summer, but the logic is that everyone rings a heating engineer in the first cold week of autumn, and by then diaries are full.

If you've already missed the summer window, book in early autumn rather than waiting for a breakdown - here's why autumn beats the winter rush. And if your warranty anniversary is coming up, book before it passes: the service needs to happen within each 12-month period to keep the warranty record unbroken.

How long does a boiler service take?

A proper service on a modern combi or system boiler takes 45 to 60 minutes. Older boilers, back boilers, or a boiler that hasn't been serviced in years can take a little longer, because there's more cleaning to do and occasionally a seized part to work around. If we're doing the service + CP12 bundle for a landlord, allow around 90 minutes for the whole visit depending on how many gas appliances the property has.

You'll need to be home to let the engineer in, and the boiler should be accessible - if it's boxed into a kitchen cupboard, clear the cupboard before we arrive and the visit runs quicker. Beyond that, there's nothing to prepare. We'll leave you with the written service record, a straight answer on the boiler's condition, and no upsell.

We're a family firm - Carlton Fuller and his sons Simon and Stephen, all Gas Safe registered - and we've serviced boilers across Surrey and South London for nearly 30 years on the same basis: fixed prices, honest advice, and no work done without your say-so. If you'd like a service booked, or just want to sanity-check a quote you've had elsewhere, get in touch or call 07956 876156.

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