Boiler Installation in London

New boiler installation across London by Gas Safe registered engineers. Post a job free and receive quotes within hours.

✓ Gas Safe registered✓ All major brands✓ Manufacturer warranty✓ Free to post
What We Cover

Boiler installation services across London

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Combi Boiler Install

New combi boiler supply and fit. Ideal for London flats and smaller houses. No cylinder required — hot water on demand.

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System Boiler Install

System boiler with hot water cylinder. Best for larger London homes with multiple bathrooms and high hot water demand.

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Heat-Only Boiler

Traditional heat-only boiler with cylinder and feed tank. Suited to older London properties with gravity-fed systems.

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Boiler Relocation

Moving a boiler to a different location — kitchen to utility room, loft, or outside flue. Full Gas Safe certification included.

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Flue Installation

New flue routes for boiler relocations or where existing flue is non-compliant. All flue work carried out to current regulations.

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Smart Controls

Smart thermostat installation — Nest, Hive, or Tado — alongside new boiler for remote control and energy saving.

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Costs

Boiler installation prices in London (2026)

JobLow estimateHigh estimate
New combi boiler (supply + fit)£1,800£3,500
System boiler (supply + fit)£2,000£4,500
Heat-only boiler£1,500£3,000
Boiler relocation£500£1,500
Magnetic filter (Magnaclean)£150£250
Smart thermostat (Nest/Hive)£200£350

Prices are estimates for London 2026. Costs vary by boiler brand, model, and installation complexity. Always get at least three quotes.

How It Works

Get a boiler installed in London in 3 steps

1

Post your job free

Describe the boiler installation needed — combi, system, or heat-only — and your London postcode. Under 2 minutes.

2

Gas Safe engineers contact you

Gas Safe registered engineers covering your area respond with quotes. They may ask to survey the property first for complex jobs.

3

Compare & choose

Review each engineer's Gas Safe number, brand experience, warranty terms, and price. No obligation.

About boiler installation in London

The choice between a combi boiler and a system boiler is particularly important in London, where property sizes and household configurations vary enormously. For the capital's many studio and one-bedroom flats, a compact combi boiler is almost always the right choice — modern units are efficient, reliable, and take up very little space. For London's larger Victorian and Edwardian family homes — particularly those with 3 or more bathrooms — a system boiler with a well-insulated hot water cylinder is generally more suitable, as it can supply multiple hot water outlets simultaneously without the flow-rate limitations of a combi. Worcester Bosch and Vaillant are the most commonly installed brands across London, with Viessmann popular at the premium end.

London's very hard water supply makes scale protection a critical consideration for any new boiler installation. Manufacturers including Worcester Bosch and Vaillant require a scale inhibitor to be fitted to maintain warranty validity in hard water areas. A magnetic boiler filter (such as a Magnaclean or equivalent) should always be installed on the heating return pipe to capture iron oxide sludge that would otherwise circulate through the new boiler. Both of these additions are modest in cost but can extend boiler life significantly and protect the manufacturer warranty — always confirm they are included in your installation quote.

FAQ

Frequently asked questions — boiler installation London

Should I get a combi or system boiler for my London property?+
For most London flats and smaller houses (up to 3 bedrooms), a combi boiler is the most practical choice — it heats water on demand with no need for a hot water cylinder, freeing up space. For larger London houses with multiple bathrooms or high hot water demand, a system boiler with a cylinder is more appropriate as it can supply hot water to multiple outlets simultaneously. A Gas Safe engineer can advise based on your property size and usage patterns.
How long does a boiler installation take in London?+
A like-for-like combi boiler replacement (same location, same fuel type) typically takes one day. A new boiler installation in a different location, or a full system change from heat-only to combi, may take 1–2 days. More complex installations involving flue routing changes or pipework alterations take longer. Your engineer should give you a time estimate before work begins.
What are the best boiler brands for London's hard water?+
Worcester Bosch and Vaillant are the most popular boiler brands in London and both perform well in hard water conditions. Viessmann is a premium German brand with excellent reliability and 10-year warranty options. All three manufacturers recommend fitting a scale inhibitor and magnetic filter (such as a Magnaclean) in London's hard water areas to protect the boiler and maintain warranty validity. Ideal and Baxi are good mid-range options.
What warranty comes with a new boiler installation in London?+
Manufacturer warranties for new boilers typically range from 2 to 10 years, depending on brand and model. Worcester Bosch offers up to 10 years when installed by a Worcester Accredited Installer. Vaillant offers up to 10 years with a VaillantPRO installer. Warranties usually require annual servicing by a Gas Safe engineer to remain valid. Always confirm warranty terms and conditions with your installer before purchase.
How do I choose the right boiler size for my London home?+
Boiler size (output in kW) depends on the size of your home, number of radiators, and hot water demand. A small flat might need an 18–24kW combi, while a large 4-bedroom house with multiple bathrooms might need a 35–40kW system boiler. An undersized boiler will struggle to heat your home efficiently; an oversized one wastes energy. A Gas Safe engineer will assess your property and recommend the correct output.
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