Combi boiler cost explained for flats vs houses
What London homeowners actually pay
Most “combi boiler prices” online are boiler-only numbers. Real installed cost depends on the property.
For the wider picture, see: new boiler cost and installation in London.
Typical installed range in London for most combi swaps & installs.
Access, flue routing and gas supply are the usual cost split.
Boiler + pipework + flue route photos usually enable a realistic estimate.
Typical combi boiler installation cost in London
In London, most combi boiler installations land between £2,800 and £4,800 all-in.
If you’re looking for the main service page (the one to book / enquire from), use: Boiler Installation London.
| Combi boiler type | Typical total installed cost | Who it suits |
|---|---|---|
| Entry-level combi | £2,800 – £3,400 | Smaller flats, one bathroom, modest hot water demand |
| Mid-range combi | £3,300 – £4,100 | Most London homes with 1–2 bathrooms |
| Premium combi | £4,000 – £4,800+ | Higher hot water use, better build, longer warranties |
The boiler model matters, but the quote is often decided by the property constraints: flue route, gas supply, pipework condition, and access.
One of the biggest reasons quotes change is what’s included (or quietly left out) — here’s a quick list of costs people miss when getting a new boiler.
Combi boiler cost: flats vs houses in London
This is where prices really diverge.
Flats (especially above shops)
- Flue limitations: longer runs / restricted terminals / managed routes
- Access and parking: stairs, permits, time windows
- Gas supply quirks: older pipe sizes, pressure limitations
- Management/admin: permissions, neighbour timing constraints
This is why some flat installs land closer to £3,500–£4,500.
Houses
- Higher output needs: more bathrooms and higher hot water draw
- Old pipework: upgrades needed for proper flow
- Relocations: moving the boiler adds labour and materials
- Extras: flushing, filtration, controls upgrades
Straightforward house swaps can start cheaper, but larger homes can exceed flat pricing.
If you want the full breakdown beyond combis, jump to new boiler cost and installation in London.
Realistic model examples (installed ranges)
| Combi boiler model | Typical installed range | Best for |
|---|---|---|
| Ideal Logic+ Combi | £2,900 – £3,500 | Smaller homes wanting a sensible option |
| Baxi 600 / 800 Combi | £3,100 – £3,800 | Strong value installs with good parts availability |
| Vaillant ecoTEC Plus | £3,600 – £4,400 | Premium reliability and longer-term ownership |
| Worcester Bosch Greenstar | £3,700 – £4,600 | Premium builds with strong installer support |
If pipework, flue route, or gas supply needs changes, the price moves. If you’re ready to speak to an engineer about your own setup, use Boiler Installation London.
What actually changes your combi boiler quote?
Technical factors
- Gas pipe sizing
- Microbore pipework
- Flue route constraints
- System condition
Practical factors
- Access
- Timing constraints
- Relocations
- Controls & compliance
A lot of “cheap” quotes ignore the extras that keep the boiler running properly long-term. If you’re comparing numbers, check the costs people miss when getting a new boiler.
How to get an accurate combi boiler price (without a sales pitch)
| What to send | Why it matters |
|---|---|
| Photo of the boiler front | Identifies current type and typical swap complexity |
| Photo of pipework underneath | Shows condition, valves, filters, likely upgrade needs |
| Photo of the flue (inside and outside if possible) | Confirms routing constraints |
| Flat/house + number of bathrooms | Helps size the boiler correctly |
If the job is simple, we’ll tell you. If something will push cost up, we’ll tell you that too.
How this compares to full new boiler costs across London
Use our hub for the full comparison: new boiler cost and installation in London.
If you want the actual service / booking page, go here: Boiler Installation London.
Combi boiler cost FAQs (London)
Is a combi boiler cheaper to install in a flat than a house?
Often, but not always. Access, flue limitations and building constraints can push flat installs higher.
What’s a realistic installed cost for a combi boiler in London?
Most installed combi boiler jobs land between £2,800 and £4,800 depending on constraints.
Why do quotes vary so much for the “same” combi boiler?
Gas pipe sizing, pipework condition, flue routing, access constraints and relocations change labour/materials.
Do combi boilers struggle with multiple bathrooms?
They can if two showers are used at once. In some homes a cylinder setup is a better fit.
What should I send to get an accurate combi boiler quote?
Boiler photo, pipework photo, flue route, flat/house + bathrooms.
Need a straight combi boiler price for your flat or house?
Call +44 7727 154746 or start here: Boiler Installation London.