How much does a boiler service cost in London?

People searching for a boiler service in London usually want one number. The honest answer is a range, plus a short list of things that move a quote up or down. This guide gives you the published figures, explains where London jobs differ, and shows how to compare quotes so you are paying for a real service.

The published figures

We do not invent prices. The most useful public figures come from the Checkatrade boiler service cost guide, whose table was last updated in March 2026. These are UK averages, not London quotes.

Job	Checkatrade UK figure
One off gas boiler service	£80 to £120, average about £100
Landlord gas safety certificate, one boiler and one hob or fire	from £60 to £90
Boiler repair	£120 to £750

Checkatrade labels its table as cost plus VAT. Always check whether a quote you get includes VAT.

Why a London quote can differ

Access

A lot of London homes are flats in converted Victorian houses. The boiler went wherever there was space when the flats were made: a high kitchen cupboard, a hall cupboard, a loft above the top flat. An engineer needs room to take the case off, clean inside and work safely. A loft boiler reached by a ladder, or a cupboard with shelves built round it, takes longer.

Basements are common too, especially in places like Fulham where many terraces have been dug down. Basement boilers often drain through a small condensate pump rather than straight outside, which adds a part to check.

Boiler type

A combi boiler has fewer extra parts than a system or regular boiler with a hot water cylinder. With a cylinder, the engineer also checks the pump, motorised valves and cylinder thermostat. An unvented cylinder, a sealed tank fed from the mains, has safety valves that makers ask to be checked regularly. See our system and regular boiler service page for what that adds.

Landlord checks

A gas safety record must cover every gas appliance and flue the landlord provides. A flat with a combi and a gas hob is quicker than a house with a boiler, a hob and a gas fire. If you want a full service and the safety check at the same visit, the engineer is doing two jobs, though one visit is usually cheaper than two.

Parking and travel

Most streets in south and west London are in controlled parking zones run by councils such as Lambeth, Wandsworth and Hammersmith and Fulham. Some engineers build parking costs into their price. Tell the company whether there is a driveway, a permit you can share, or a free bay nearby.

Parts found at the service

Some makers ask for certain seals or gaskets to be replaced whenever the burner is removed. A service can also uncover a worn electrode, a blocked condensate trap or a flat expansion vessel. These are extra work and should be priced before they are done.

What a full service includes

A cheap service is only good value if it is a full service. A proper one includes:

• Checking the gas supply pressure at the boiler
• Removing the case and inspecting the burner, heat exchanger, fan, seals and electrodes
• Cleaning the condensate trap
• Checking the flue inside and the terminal outside
• A combustion test with a flue gas analyser, with readings written down
• Checking system pressure, the expansion vessel and the pressure relief valve
• Checking controls, and on combis, the hot water flow and temperature
• A written service record and the Benchmark section of your manual filled in

Our post on what a boiler service includes goes through each step.

Questions to ask before you book

Ask	Why it matters
Will the case come off?	Without it, the inside cannot be checked or cleaned
Will you do a combustion test and write down the readings?	It is the only real measure of how the boiler is burning
Is a landlord gas safety record included?	It is a separate document
Is VAT included?	Avoids a surprise on the invoice
What happens if you find a fault?	You want a price before any work
Are you Gas Safe registered for this work?	It is the law for gas work

Gas work in the UK must be done by a Gas Safe registered engineer. Ask to see the ID card on arrival and check the licence number on the Gas Safe Register. The back of the card lists the types of work the engineer is qualified to do.

Is it worth paying for a service every year?

There are three reasons most London homeowners do.

First, the warranty. Worcester Bosch says yearly servicing is a condition of its guarantee. Vaillant says the boiler must be serviced annually. Other makers have similar wording. A missed service can make a claim harder. Our boilers we service page quotes each maker.

Second, hard water. Thames Water says all the water in its region is hard. On combis, scale slowly builds up inside the part that heats tap water. A yearly service is when it gets spotted.

Third, safety. A combustion test is how carbon monoxide problems get caught before anyone notices symptoms.

Spreading the cost

Some people prefer a monthly service plan. Others pay once a year. A plan that only covers the service is different from boiler cover, which is insurance for repairs. Before signing up to anything, read our boiler service plans explained page.

Getting a firm price

Our boiler service price guide sets out the same cost drivers in brief. The easiest way to get a firm price is to give the basics when you ask: boiler make and model, rough age, where it sits, whether you have a cylinder, whether you need a landlord record, and the parking situation. With that, a company can quote properly before the visit. For homes in SW6, our Fulham area page covers the basement and lettings details that affect a visit there.