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.
About this service
Boiler installation London — what you need to know
Choosing the right boiler for your London property
The right boiler for a London property depends on the size of your home, how many bathrooms you have, your existing pipework and the available space. For the majority of London flats and smaller terraced houses — one or two bathrooms, a limited airing cupboard, no loft access — a modern combi boiler is the practical default. It requires no hot water cylinder, no cold water storage tank in the loft, and the entire unit fits inside a standard kitchen cupboard. Today's A-rated combis from Worcester Bosch and Vaillant achieve over 90% seasonal efficiency and respond to demand within seconds.
Larger Victorian and Edwardian terraces across areas like Islington, Hackney and Wandsworth often benefit more from a system boiler paired with an unvented (pressurised) cylinder. This configuration delivers mains-pressure hot water to multiple bathrooms simultaneously — important in a four-bedroom house where two showers may run at the same time. Flow rates of 25–40 litres per minute are achievable, which is simply not possible with a combi on a standard London supply.
For older properties with an existing vented system in good condition — a header tank in the loft and a hot water cylinder in an airing cupboard — a heat-only (regular or conventional) boiler replacement is often the most cost-effective route. We retain the existing infrastructure and swap only the boiler, keeping disruption and cost to a minimum.
On brands: we install Worcester Bosch, Vaillant, Baxi, Ideal, Viessmann and Glow-worm. Worcester Bosch offers up to 12 years manufacturer guarantee on selected Greenstar models when installed by an Accredited Installer — we hold that status. Vaillant ecoTEC ranges carry up to 10 years. Baxi and Ideal are excellent mid-market choices for buy-to-let landlords and budget-conscious homeowners. Viessmann Vitodens are the premium option where long-term running cost efficiency is the priority.
Boiler installation in London flats — the specific challenges
Flats present a distinct set of challenges that require experience specific to London's housing stock. Flue routing is the most common complication: in a flat you cannot always run a standard horizontal flue through an external wall. Vertical flues through the roof, extended horizontal flues through communal spaces, or flues routed via a purpose-built flue shaft are all scenarios our engineers have handled across London — from purpose-built 1960s blocks in Lewisham to converted period buildings in Kensington.
In leasehold flats, any work that affects shared infrastructure — external walls, roof spaces, communal risers — typically requires written consent from the building management company or freeholder before work begins. We advise on what consent is needed and what technical drawings or specifications the managing agent may require to approve the work.
Working in limited spaces is second nature to our engineers. We carry compact boiler models specifically suited to tight cupboard installations, and we have the access equipment to work in plant rooms, roof spaces and restricted meter cupboards without causing damage to surrounding fixtures.
With over 180 verified reviews across Checkatrade (60 reviews) and MyBuilder (120 reviews), and installations completed across all 33 London boroughs, we have the depth of experience to handle the full range of London property types — from studio flats in zone 2 to large detached houses in the outer boroughs.
Gas Safe certification and Building Regulations
Every boiler installation in the UK must be carried out by a Gas Safe registered engineer. Gas Safe is the official gas registration body — it is a legal requirement under the Gas Safety (Installation and Use) Regulations 1998. You can verify any engineer's registration at gassaferegister.co.uk before work begins. Our Gas Safe registration number is displayed on all quotations and job sheets.
Beyond Gas Safe, new boiler installation is notifiable work under Building Regulations Part L and Part J. As a Gas Safe registered business, we are authorised to self-certify the installation and notify Building Control directly on your behalf — you do not need to make a separate application or pay a local authority inspection fee. We issue a Gas Safe Installation Certificate, complete the Benchmark commissioning document, and provide you with digital copies of all paperwork on the day of installation. This documentation is important: mortgage lenders and solicitors will ask for it when you sell.
How long does a boiler installation take?
Most London boiler swaps — like-for-like combi replacements in a house or flat — are completed within a single working day. We arrive in the morning, drain the system, remove the old boiler, fit and commission the new unit, and leave you with full heating and hot water by late afternoon. For jobs that involve a system conversion (switching from a heat-only system to a combi, or upgrading to a system boiler with a new unvented cylinder), or where new pipework runs are required across multiple rooms, the work may extend to two days.
A boiler installation in a flat with complex flue routing or building management approval requirements may also take longer to schedule, though the physical installation itself is typically still one day once the necessary consents are in place. We always give you a realistic timeline before work starts — no surprises.
Combi boiler vs heat pump — what is right for London in 2025?
Heat pumps are the long-term direction of travel for UK domestic heating, but for most London terraces and flats today, a new A-rated combi boiler remains the most practical and cost-effective choice. Heat pumps require external space for the outdoor unit — not always available in a London flat or a terrace with a small rear garden. They also work most efficiently with a well-insulated property and larger radiators or underfloor heating. A Victorian terrace with single-skin walls and original-sized radiators is unlikely to be a good candidate without significant additional investment in insulation and radiator upgrades.
A new A-rated gas combi boiler, by contrast, can reduce fuel consumption by 20–30% compared to a 15-year-old boiler simply through improved efficiency. For many London homeowners, a new boiler now with a pathway to electrification later — when the building fabric is improved — is the pragmatic decision. We will always give you an honest assessment of your options rather than defaulting to the most expensive route.
We also offer same-day attendance for emergency boiler failure during the heating season. If your boiler has broken down and you need heat today, call us — we cover all 33 London boroughs and aim to attend on the same day for confirmed boiler replacement jobs where a repair is not viable.
Transparent pricing
£1,500–£3,500
Installed — including parts, labour and disposal of your old boiler. Exact price confirmed in writing before work begins. No hidden charges.
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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