Key Takeaways
- A new boiler fitted typically costs £1,800 to £3,000, with a wider range of £500 to £4,500 depending on type and complexity (GreenMatch, 2025).
- Combi boilers suit most London flats and smaller homes; system boilers suit larger homes with several bathrooms.
- Replacing the boiler during a renovation avoids disruption later and lets you reposition it.
- A new A-rated boiler cuts running costs and is far more efficient than units over 10 to 15 years old.
- Always use a Gas Safe registered engineer.
A new boiler is often part of a wider renovation, and getting the type and position right pays off in comfort and running costs for years. Here is what a new boiler costs in London in 2026 and how to choose.
How much does a new boiler cost?
A new boiler fitted typically costs £1,800 to £3,000, with the full range running from around £500 for a basic like-for-like swap to £4,500 for a high-output system boiler with significant pipework changes, according to GreenMatch 2025 data. The price depends on the boiler type, output, brand and how much pipework needs altering.
| Scenario | Typical cost (fitted) |
|---|---|
| Like-for-like combi swap | £1,800 to £2,500 |
| System boiler (larger home) | £2,500 to £3,500 |
| Boiler move or system conversion | £3,000 to £4,500+ |
Which boiler type should you choose?
- Combi boiler: heats water on demand with no tank, saving space. Ideal for most London flats and smaller homes with one bathroom.
- System boiler: works with a hot water cylinder and suits larger homes with several bathrooms, where more than one shower may run at once.
- Conventional (heat-only): uses a tank and cylinder, usually retained in larger period properties with existing systems.
Replace it during your renovation
If your boiler is over 10 to 15 years old, replacing it during a renovation is the sensible time, because pipework changes and any repositioning happen while walls and floors are already open. A new A-rated boiler is far more efficient and cuts running costs. Always use a Gas Safe registered engineer. We include heating upgrades in our full house renovations. For a quote, contact us or call 07472 424 226.