If you’re researching the boiler installation cost in London, you’ve probably already seen wildly different prices online.
One company advertises installations from £1,800, while another quotes £4,000+ for what looks like the same job. The reality is that the cost of installing a boiler in London depends on far more than just the boiler itself.
In this 2026 guide, we’ll cover:
Average boiler installation costs in London
What affects the final price
When cheap quotes should raise concerns
How to reduce long-term heating costs
Most homeowners in London can expect the boiler replacement cost in London to fall between £2,000 and £4,500, depending on the work required.
| Type of Installation | Typical Cost Range |
|---|---|
| Like-for-like boiler replacement | £2,000 – £2,800 |
| Combi boiler installation | £2,200 – £3,200 |
| System change (conventional → combi) | £3,000 – £4,500+ |
| Full central heating installation | £4,500 – £7,000+ |
For a full breakdown of what’s included, visit our
new boiler installation page.
A-rated boilers installed from £1795
1.Boiler Type
The type of boiler you choose has a major impact on the new boiler cost in London.
Combi boilers are usually cheaper to install
System and regular boilers may need extra components
Older systems often require more labour
Choosing the correct boiler during your
new boiler installation helps avoid unnecessary future costs.
2.System Changes & Conversions
Switching from a conventional boiler to a combi system increases costs due to:
Removal of tanks and cylinders
Pipework alterations
System flushing and balancing
Although more expensive upfront, conversions often improve efficiency and free up space.
3.Property Size & Layout
Larger homes may require:
Higher-output boilers
Longer pipe runs
Additional radiators
Older London properties, flats, and listed buildings can also increase labour time during a professional boiler installation.
| Additional Work | Why It Affects Cost |
|---|---|
| Gas pipe upgrade | Required to meet current safety standards |
| System flushing | Ensures boiler efficiency and warranty protection |
| Smart heating controls | Improves efficiency but increases install cost |
A very low quote often means something important has been left out.
Common omissions include:
Proper system flushing
Safety checks and testing
Correct boiler commissioning
Manufacturer registration
This is why a proper survey or survey via pictures is far more reliable than instant online prices.
Get complete boiler cover from £12p/m
Many homeowners delay replacement because of the upfront cost, but repeated repairs can quickly outweigh the price of a new boiler.
| Scenario | Typical Outcome |
|---|---|
| Boiler under 8 years old | Repair usually makes sense |
| Boiler 10–12+ years old | Replacement often cheaper long-term |
| Frequent breakdowns | Replacement usually recommended |
This is also where boiler cover plans and home care plans can help protect your investment after installation.
You can reduce long-term costs by:
Installing the correct boiler size
Using modern heating controls
Servicing the boiler annually
Protecting the system with ongoing cover
A correctly installed boiler should last 12–15 years with proper maintenance.
The only reliable way to know how much a boiler installation costs is through a professional assessment that considers:
Your property
Your current heating system
Your hot water usage
If you’re considering replacement, our boiler installation service offers clear advice, transparent pricing, and fully qualified gas safe engineers.
Get complete boiler cover from £12p/m
A-rated boilers installed from £1795
Book your boiler service for just £108
Boiler not working? We’ll fix it from £108
Premium cylinders installed from £1599
Free survey & quote for all ASHP installs
