boilers
New Boiler Cost London 2025: What to Budget for Replacement
New Boiler Costs in London 2025
Boiler replacement costs in London vary significantly depending on boiler type, brand, and installation complexity. Here is what you should expect to pay for a like-for-like replacement:
Combi Boiler Replacement London
- Budget brand (Ideal, Baxi, Glow-worm): £1,800–£2,400 supply and fit
- Mid-range (Vaillant ecoFIT, Worcester Greenstar i): £2,200–£3,000 supply and fit
- Premium (Viessmann Vitodens, Worcester Greenstar 8000): £2,800–£3,800 supply and fit
System Boiler Replacement London
- System boiler only (cylinder already exists): £2,000–£3,200 supply and fit
- System boiler with new hot water cylinder: £2,800–£4,500 supply and fit
What Affects New Boiler Cost in London
- Flue route — a simple horizontal flue is cheapest; a vertical flue through a roof adds £150–£400
- Moving the boiler location — new pipework runs add £200–£600+
- System upgrades required — magnetic filter, scale reducer (hard water), new controls
- Asbestos insulation on old pipes — requires specialist removal in pre-1980 London properties
- Access difficulties — loft, basement or cabinet installation adds labour time
Frequently asked questions
Is it worth paying more for a premium boiler in London?
Premium boilers (Viessmann, Worcester Bosch 8000, Vaillant ecoTEC Plus) typically offer longer manufacturer warranties (5–7 years vs 2 years), higher efficiency ratings, and better reliability over 15+ years. For London properties that are rented out, the reduced risk of boiler breakdown and associated landlord obligations often justifies the additional upfront cost.
Can I get a boiler replacement grant in London?
The Boiler Upgrade Scheme (BUS) provides grants for heat pump installations (£7,500 for air source, £7,500 for ground source) as part of the move away from gas boilers. However, standard gas boiler replacements do not qualify for BUS grants. Some London boroughs have additional fuel poverty schemes for eligible households — check with your local authority.
How long does a new boiler installation take in London?
A like-for-like combi boiler replacement in a London flat or house typically takes 1–2 days. More complex installations — moving the boiler, system conversion, or adding new controls — take 2–3 days. Replacing a conventional system with a combi boiler (removing the cylinder and header tank) takes 2–3 days including making good.