Boiler Installation Cost London
London · 1.35x regional multiplier
£115 – £216
Independent London benchmark for heating system (boiler, radiators & repair). Answer a few questions for your exact figure.
Free · No obligation · Independent UK pricing
New Boiler Cost in London (2026)
A new combi boiler fitted in London starts at £2,525, based on the InstantCost boiler calculator's London model. That price covers a like for like combi swap with a budget brand boiler. Prices last updated October 2026.
How much do other boiler installations cost in London?
Other jobs cost more than a budget combi swap, depending on the boiler brand and how much of your heating system changes.
Installation scenario | Starting price |
|---|---|
Like for like combi swap, mid range brand (such as Vaillant) | £2,726 |
Like for like combi swap, premium brand (such as Worcester Bosch) | £2,979 |
Boiler relocation | £2,984 |
New system boiler | £3,098 |
New conventional (heat only) boiler | £3,443 |
System to combi conversion | £3,672 |
Full central heating installation | £5,164 |
These are starting prices from the InstantCost calculator. Your final price depends on your home, the boiler you choose, pipework and access, so always get a fixed written quote from a Gas Safe registered engineer.
What's included in a new boiler price?
A starting price covers the basic job. Some items are normally part of it, while others are often added as extras, so check your quote line by line.
Usually included | Often charged as extra |
|---|---|
The new boiler | Removing and disposing of the old boiler |
Labour to fit it in the same position | Moving the boiler to a new position |
Connection to your existing pipework | A longer or vertical flue |
A standard flue | Power flush or chemical flush |
Commissioning and testing | Magnetic system filter |
Smart thermostat or upgraded controls |
Ask every installer whether VAT is included, because some London quotes show prices without it.
How much do common extras cost?
Extra | Starting price |
|---|---|
Flue extension | £90 |
Magnetic system filter | £120 |
Smart thermostat | £150 |
Old boiler removal and disposal | £150 |
Power flush | £350 |
Moving the boiler to a new position | £400 |
System to combi conversion work | £600 |
How do London boiler prices compare with the rest of the UK?
London is the most expensive region for a new boiler on our calculator. A budget combi swap here costs about 30% more than in Birmingham and almost 60% more than in Wales.
Region | New budget combi boiler, starting price |
|---|---|
Midlands (Birmingham) | £1,964 |
Manchester and Liverpool | £1,870 |
Leeds and Sheffield | £1,720 |
Scotland | £1,646 |
Wales | £1,590 |
You can follow regional prices for every home service in the InstantCost UK Price Index.
What about towns just outside London?
All 32 London boroughs and the City of London share one London price. Towns just beyond the capital are priced on our South East model, which is cheaper for the same job.
Place | New budget combi boiler, starting price |
|---|---|
Watford, St Albans, Slough, Woking, Epsom, Reigate, Dartford, Sevenoaks, Brentwood and Harlow | £2,244 |
What makes a boiler installation cost more in London?
Road charges
Every van driven into central London pays the Congestion Charge of £18 a day, from 7am to 6pm on weekdays and from 12pm to 6pm at weekends and on bank holidays. The Ultra Low Emission Zone covers every borough and charges non-compliant vans £12.50 a day. Most installers drive compliant vans, but many pass the Congestion Charge on for central jobs. A swap normally takes a full working day, so a weekday installation inside the zone is hard to do without it.
Parking
Much of inner London has controlled parking zones. An installer may need a visitor permit from you or a paid bay nearby. Have a permit ready and ask whether parking is covered in the quote.
Hard water
London has some of the hardest water in the UK. Limescale builds up inside boilers, especially in the heat exchanger of a combi, and can shorten a boiler's life. Many London installers recommend a scale reducer on the mains supply, so ask if one is included.
Flats and flue rules
The flue on a flat has to meet strict distance rules from windows, doors, balconies and neighbouring properties. In some flats, the only legal position needs a longer flue or a vertical flue through the roof, which adds cost. The engineer should survey your flat before giving a fixed price.
Conservation areas and listed buildings
Large parts of London are conservation areas, and some homes are listed. A new flue on the front of a listed building, or in some conservation areas, may need consent from the council. Check before you book, especially if the boiler is moving.
Which London homes suit which setup?
Home | Typical setup |
|---|---|
Conversion flat in a Victorian house | Boiler fitted in a kitchen or hallway cupboard, where space is tight |
Victorian or Edwardian terrace | Boiler often in the kitchen, with pipework running through suspended timber floors |
1930s semi in outer London | Often still on a conventional system with tanks in the loft |
Mansion block flat | Flue position is usually the main challenge |
New build flat | Often connected to a communal heat network instead of having its own boiler |
If your building runs on a communal heat network, you'll have a heat interface unit rather than a boiler. Talk to your building manager before you ask for boiler quotes.
Which type of boiler do you need?
Boiler type | How it works | Best for |
|---|---|---|
Combi | Heats water instantly from the mains, with no tank | Flats and homes with one bathroom |
System | Stores hot water in a cylinder, with no loft tanks | Homes with two or more bathrooms |
Conventional (heat only) | Uses a cylinder and cold water tanks in the loft | Older homes with low water pressure |
Should you repair or replace your boiler?
Repair it if the boiler is under 10 years old and the fault is minor. A fault diagnosis and repair in London starts at £195, and an annual service at £115.
Think about replacing it if the boiler is 10 to 15 years old or more, breaks down often, or needs an expensive part. A new control board starts at £413 and a new circulating pump at £436, which is a big spend on an ageing boiler.
What safety and legal rules apply?
Gas Safe registration: all gas work must be carried out by an engineer on the Gas Safe Register who is qualified for boilers. Ask for their Gas Safe ID card and check it on the Gas Safe Register website.
Building Regulations: a new gas boiler must be notified to the local council. Your Gas Safe engineer handles this, and you'll receive a compliance certificate. Keep it for when you sell your home.
Boiler Plus: in England, a new combi boiler must be fitted with at least one extra energy saving measure, such as a smart thermostat with automation or weather compensation.
Carbon monoxide: fit an alarm near the boiler. Rented homes in England with a gas boiler must have one by law.
Gas leaks: if you smell gas, open windows, don't use switches or flames, leave the property and call the National Gas Emergency Service on 0800 111 999.
Can you get help paying for a new boiler?
Some households on qualifying benefits can get a free boiler through the ECO4 scheme, which closes on 31 December 2026. From 2027, support moves to the government's Warm Homes Plan, run mainly through local councils.
London boiler installation questions
How long does a boiler installation take?
A like for like combi swap usually takes one day. A conversion, relocation or full central heating job can take two to five days.
Will I be without heating and hot water?
Yes, for most of the installation day. For a straight swap, the old boiler is usually switched off in the morning and the new one is working by the evening.
What size boiler do I need?
That depends on how many bathrooms you have and how much hot water you use at once. Your engineer should work out the right output in kW from your home's size and hot water needs, rather than simply copying your old boiler.
Do I need to be home during the installation?
Someone should be there at the start to let the engineer in and agree where everything goes, and at the end to be shown how the new boiler and controls work.
Can I buy my own boiler and pay someone to fit it?
Some installers will fit a boiler you've bought, but many won't. You may also lose access to the longer manufacturer warranties that come through accredited installers, so ask before you buy.
Should I clear space before the engineer arrives?
Yes. Empty the cupboard around the boiler, clear a path from the front door, and move anything stored near the loft hatch or airing cupboard if those areas are part of the job. It saves time on the day.
Related guides
Boiler installation cost UK: national prices and the full calculator.
Free boiler grants: who qualifies for help with a new boiler.
UK Price Index: monthly regional prices for every service.
Cost guides and advice: practical price guides before you book.
How we calculate these prices
Every price on this page is a modelled starting price from the InstantCost boiler calculator, using the London region, or the South East region for towns outside London. Prices assume a scheduled visit and an existing boiler aged 5 to 10 years. The calculator prices by region rather than by borough, so it doesn't reflect differences between individual parts of London. Prices were last updated in October 2026 and may change. InstantCost is an independent price comparison service and does not install boilers.
Frequently asked questions
Related guides & calculators
London benchmark
£115 – £216