Boiler replacement in London
Typical prices up front, then a fixed quote from a Gas Safe registered installer working in your part of London.
London homes, and the boilers that fit them
Most London homes fall into three groups: Victorian and Edwardian terraces, flats carved out of those houses or built as blocks, and 1930s semis further out. Space is usually the deciding factor. A combi saves a cupboard, but a busy terrace with two bathrooms often needs stored hot water. We help you pick the right boiler for your home, then you get a fixed price.
Victorian and Edwardian terraces: A combi often sits in the kitchen or a rear extension. Houses with two bathrooms or a loft conversion usually do better with a system boiler and an unvented cylinder.
Converted flats and mansion blocks: Flue position is the main limit, especially in a conversion where the boiler sits in an internal cupboard. Some need a plume kit or a vertical flue through the roof.
Outer-borough 1930s semis: Plenty of these still have a regular boiler and a loft tank. A combi conversion frees the loft but needs a good mains water flow to work well.
Boiler replacement prices in London
| Job | Typical price | Fitting time |
|---|---|---|
| Combi to combi swap | £2,200 to £3,400 | 1 day |
| System or regular to combi | £3,000 to £4,200 | 1 to 2 days |
| System boiler replacement | £2,800 to £4,000 | 1 to 2 days |
| Boiler and full system flush | add £300 to £500 | same day |
Typical prices including VAT, checked October 2026. Your installer gives you a fixed price in writing before any work starts. More detail in our boiler replacement cost guide.
Thinking about a heat pump instead?
With the £7,500 grant, a heat pump can cost less than you think in a well-insulated London home.
Is a heat pump right for you?Areas we cover around London
- Islington
- Hackney
- Camden
- Brixton
- Wimbledon
- Ealing
- Croydon
- Walthamstow
- Greenwich
- Richmond
Also nearby: Boiler replacement in Reading, Boiler replacement in Luton, Boiler replacement in Chelmsford, Boiler replacement in Brighton
Boiler replacement in London: questions
What does a new boiler cost in London?
A like-for-like combi replacement usually costs £2,200 to £3,400 fitted, VAT included. Swapping a regular or system boiler for a combi costs more, typically £3,000 to £4,200, because the tanks come out and pipework changes. The price is fixed in writing before work begins.
Can I have a combi in a flat with no outside wall near the boiler?
Often, yes. Installers can run a longer horizontal flue or go up through the roof on a top-floor flat. If neither works, moving the boiler may be the answer. The survey settles which option applies to your flat.
Is a combi right for a London terrace with two bathrooms?
Not always. A combi heats water on demand, so two showers at once can struggle, especially where mains pressure is weak. A system boiler with an unvented cylinder handles that better. Your installer tests your water flow before recommending one.
Will parking or access affect the install?
It can add time on busy streets, since engineers need to unload the boiler and old parts. Mention any parking permits or access limits when you book, so the installer can plan for it.