Boiler Installation — London
New boiler installation in London
Gas Safe registered engineers supply and install all major boiler brands across all 33 London boroughs. Combi, system and heat-only boilers. 10-year warranties available. Benchmark commissioning document and Gas Safe notification included.
Boiler types
Which type of boiler do you need?
Combi boiler
Best for: flats and smaller homes
A combi boiler provides central heating and instant hot water in a single unit — no separate cylinder or cold water tank. It heats water on demand directly from the mains, so there is no stored hot water to run out. Modern high-efficiency combi boilers achieve SEDBUK Band A efficiency ratings (90%+). Ideal for London flats, one and two-bedroom properties, and homes with a single bathroom.
- No hot water cylinder or storage tank needed
- Faster hot water — heated on demand
- Space-efficient — fits in a kitchen cupboard
- Lower installation cost for smaller properties
System boiler with unvented cylinder
Best for: larger homes and HMOs
A system boiler works with a sealed, pressurised (unvented) hot water cylinder to deliver mains-pressure hot water to multiple outlets simultaneously — ideal for London houses with two or more bathrooms, HMOs, and properties with a high hot water demand. The cylinder stores a large volume of hot water ready for use, eliminating wait times. G3-certified installation required for the unvented cylinder.
- Mains pressure hot water to multiple outlets simultaneously
- High flow rates — 25-40 L/min
- No loft tank — cleaner installation
- Suitable for large households and HMOs
Heat-only (regular) boiler
Best for: retaining existing vented system
A heat-only boiler (also called a conventional or regular boiler) works with a hot water cylinder in an airing cupboard and a cold water storage tank in the loft. Common in older London homes built before the 1990s. Replacing like-for-like is often the most cost-effective option where an existing vented system is in good condition. Outputs up to 40kW make them suitable for larger homes with many radiators.
- Like-for-like replacement — less disruption
- Suitable for low mains water pressure areas
- Compatible with solar thermal systems
- Established system — well-understood by engineers
Brands
All major boiler brands installed
We supply and install all major boiler brands and can advise on the best choice for your property, system type and budget. We are approved installers for Worcester Bosch and Vaillant, enabling extended manufacturer warranties.
Worcester Bosch
Market leader for reliability. 10-year warranty available via Accredited Installer programme. Greenstar range covers 25-40kW outputs. Most popular choice in London residential market.
Vaillant
German engineering. ecoTEC Pro and Plus ranges. 5-10 year manufacturer warranty. Excellent spare parts availability. Compatible with Vaillant sensoCOMFORT smart controls.
Baxi
Strong reliability record. Platinum and 800 ranges. 7-10 year warranty options. Competitive pricing makes it a popular choice for rental properties and budget-conscious homeowners.
Ideal
UK manufactured. Logic+ and Vogue ranges. Up to 12-year warranty. Good value for landlord properties. Straightforward to service — parts widely available across London.
Viessmann
Premium German brand. Vitodens 100-W and 200-W. Up to 98% efficiency. Popular in high-specification London properties and where running cost minimisation is the priority.
Glow-worm
Budget-friendly option. Energy 7 and Flexicom ranges. 2-7 year warranty. Manufactured by the same group as Vaillant. Good choice for straightforward replacement on a tighter budget.
Also install: Potterton, Intergas, Alpha, Grant, Ferroli, Ariston and other brands on request.
What is included
New boiler installation — what we include
Supply of new boiler (manufacturer of your choice)
Removal and disposal of old boiler
New flue system where required
New controls, programmer and room thermostat
Magnetic system filter (ADEY MagnaClean or similar)
Chemical flush and inhibitor treatment
Benchmark commissioning documentation
Gas Safe notification to Building Control
Manufacturer warranty registration
Full system test and pressure check
Operation demonstration for homeowner
Digital copy of all paperwork issued same day
FAQ
New boiler questions answered
How much does a new boiler cost in London?
New boiler installation costs in London typically range from £1,800-2,500 for a like-for-like combi boiler replacement, £2,000-3,000 for a system boiler with unvented cylinder, and £2,500-4,000 for a full heat-only (regular boiler) upgrade with new cylinder and controls. These prices include supply, installation, flue extension, controls, commissioning and Gas Safe notification. Brands affect cost — Worcester Bosch and Vaillant command a premium over Baxi and Ideal. Prices vary depending on the location, accessibility and extent of any additional pipework or controls work required.
Which boiler brand should I choose?
Worcester Bosch and Vaillant are consistently rated highest for reliability in the UK. Worcester Bosch offer 10-year warranties on selected models when fitted by an Accredited Installer. Vaillant ecoTEC ranges carry 5-10 year warranties. Baxi and Ideal are good mid-range options with lower upfront costs. Viessmann Vitodens offer excellent efficiency (up to 98% AFUE) and are popular in high-end properties. We are approved installers for all major brands and will recommend the most appropriate model for your property type, system configuration and budget.
How long does a boiler installation take?
A straightforward like-for-like combi boiler replacement typically takes one day. A more complex installation involving system conversion (e.g., from regular to combi), new unvented cylinder fitting, or significant pipe rerouting may take two to three days. We aim to leave the property with full heating and hot water at the end of each working day where the job spans multiple days.
What type of boiler do I need — combi, system or heat-only?
Combi (combination) boilers provide heating and instant hot water without a cylinder — ideal for flats and smaller homes with one bathroom and up to 3-4 radiators. System boilers pair with an unvented (pressurised) cylinder and suit larger homes where simultaneous demand from multiple outlets is needed — they deliver mains-pressure hot water at high flow rates. Heat-only (regular or conventional) boilers work with both a cold water storage tank and a hot water cylinder — common in older London homes with existing vented systems. We assess your property and usage pattern to recommend the right type.
Do I need Building Regulations approval for a new boiler?
Yes. New boiler installation is notifiable work under Building Regulations Part L (conservation of fuel and power) and Part J (combustion appliances). Gas Safe registered engineers are authorised to self-certify compliance and notify Building Control directly — you do not need to make a separate application. We issue a Gas Safe Installation Certificate and submit the required notification. The documentation is important for property sale conveyancing.
Get a new boiler quote in London
We visit, assess and quote — no obligation. Same-day boiler replacement available in emergency situations.
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