Cost of boiler replacement in London
Old boiler out, new boiler in — real replacement costs
Searching “cost of boiler replacement” or “cost to replace boiler” usually means one thing: your boiler is old, unreliable, or failing — and you want to know the real price to replace it properly.
Boiler replacement is more than installation. It includes removal, disposal, system checks, and often upgrades to bring everything up to modern standards. This page breaks down what replacement actually costs in London and why prices vary so much, especially compared to the cost of installing a boiler on its own.
Quick answer: how much does boiler replacement cost?
In London, a full boiler replacement typically lands between:
- £2,800 – £3,800 for a straightforward like-for-like replacement
- £3,500 – £5,500+ when upgrades, conversions, or system work are needed
These figures usually include the new boiler, removal of the old one, installation labour, and essential system work — not just a box swap. For comparison, see how much a new boiler costs overall.
Typical boiler replacement cost breakdown
| Replacement element | Typical cost range | Why it’s needed |
|---|---|---|
| New boiler (combi/system/regular) | £1,200 – £2,600 | Modern, efficient replacement unit |
| Removal & disposal of old boiler | £150 – £400 | Safe removal, waste handling |
| Installation labour | £1,000 – £2,000 | Fit, commission, compliance |
| System cleaning / protection | £400 – £1,000 | Protects the new boiler |
| Controls / upgrades | £150 – £400 | Efficiency & compliance |
Why boiler replacement costs more than “just installation”
Replacement jobs uncover issues that installs don’t always face. Old boilers are often connected to tired systems — outdated pipework, undersized gas supplies, or radiators full of sludge. These same issues often appear during combi boiler installation projects.
- Old systems rarely meet modern boiler requirements
- Gas supplies often need upgrading
- Flue rules have changed significantly
- System cleaning becomes critical
This is why “cheap replacement” quotes often lead to repeat breakdowns.
Send photos of the boiler, pipework underneath, and flue exit. We’ll tell you whether it’s a clean replacement or likely to need upgrades.
FAQ — boiler replacement costs
Is boiler replacement the same as installation?
No. Replacement includes removal, disposal, and often system upgrades. Installation alone usually refers to fitting work only.
Can you replace a boiler in one day?
Many like-for-like replacements can be done in a day. Upgrades or conversions take longer.
Is it worth replacing an old boiler?
If breakdowns are frequent or parts are scarce, replacement is often cheaper long-term.