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Quick answer: A new boiler installation in London typically costs £1,800–£4,500 fully fitted, depending on boiler type, property access, and whether pipework or flue work is needed. A straightforward like-for-like combi swap in a flat sits at the lower end; system boiler installs or full conversions in period houses sit at the upper end. London labour rates run roughly 20–30% above the UK average, which is the main reason London quotes look higher than the national figures you’ll see quoted elsewhere.
If you’re comparing quotes for boiler installation in London right now, the range you’re seeing probably feels wide and that’s normal. Two flats on the same street can get genuinely different prices for what looks like the same job, because the boiler unit is only part of the cost. The rest comes down to access, existing pipework, and what your current flue and gas supply can actually handle. This guide breaks down exactly where that variation comes from, so you know what a fair quote looks like before you book anyone.
How Much Does Boiler Installation Cost in London, By Type?
Boiler prices are usually quoted as a single headline number, but that number hides a lot. The type of boiler you need is the single biggest factor in your final cost, because it determines both the unit price and how much labour the job needs.
| Boiler type | Typical installed cost in London | Best suited to |
| Combi boiler (like-for-like swap) | £1,800 – £3,000 | Flats, small-to-medium houses, 1–2 bathrooms |
| Combi boiler (with pipework/flue changes) | £3,000 – £4,500 | Older conversions, relocated boilers |
| System boiler | £2,600 – £4,000 | Houses with 2+ bathrooms, higher hot water demand |
| Conventional/regular boiler replacement | £2,200 – £3,800 | Older properties keeping the existing tank/cylinder setup |
Figures are 2026 market ranges for fully fitted jobs in Greater London, including unit and labour. Always get a fixed, itemised quote before booking see “What Actually Changes Your Quote” below.
Combi boilers remain the most common choice across London because they don’t need a separate hot water tank or cylinder for a real advantage in flats and smaller homes where storage space is limited. System boilers make more sense once a property has multiple bathrooms, since a combi’s on-demand heating can struggle if two showers run at the same time. If you’re not sure which category your home falls into, our engineers assess this as part of every free quote visit, rather than guessing over the phone.
Why Boiler Installation Costs More in London Than Elsewhere
It’s a fair question why does the exact same boiler, from the exact same manufacturer, cost more to install in London than in most other parts of the UK? The answer is almost entirely down to labour, not the equipment. Skilled, Gas Safe registered engineers in London are paid more than the national average, which is reflected directly in installation quotes across the industry, not just from any one company.
There’s a second factor specific to London’s housing stock. A large share of London properties are Victorian or Edwardian conversions, period houses, or purpose-built flats with shared walls and communal flue routes all of which can add time and materials to a job that would be simpler in a newer, more standardised property elsewhere in the country. This is why an accurate quote depends on a proper in-person survey, not just a phone estimate based on boiler type alone.
Flat vs. House: Why the “Same” Job Can Cost Differently
We get asked constantly why a friend’s or neighbour’s combi swap came in cheaper or more expensive than expected for what sounds like an identical job. In practice, the property type changes the job more than most people expect:
- Flats often cost more than the headline “combi swap” price suggests, because of flue routing through shared external walls, restricted terminal positions, and access logistics stairs, lift booking, or building management sign-off for anything touching a shared wall or communal flue.
- Houses, especially the Victorian and Edwardian terraces common across boroughs like Hackney and Islington, often need gas pipe upsizing. High-efficiency modern combi boilers need more gas flow than the narrow original pipework in pre-1970s properties were ever designed to carry.
- Multi-bathroom houses are usually better served by a system boiler than a combi, since simultaneous hot water demand from two bathrooms can outstrip what a combi can deliver on demand.
None of this means you’re being overcharged if your quote is higher than a generic online estimate; it usually means your property has one of these factors, and a good installer should explain exactly which one, rather than just quoting a number.
What Actually Changes Your Quote (Read This Before You Book)
Most complaints about boiler installation pricing don’t come from the boiler itself, they come from extras added on install day that weren’t mentioned in the original quote. This is the single most common source of frustration we hear about customers who’ve used other companies before finding us. Before you accept any quote, ask the installer to confirm, in writing, whether these are included:
- Flue extension or rerouting
- Gas pipework upsizing
- Removing an old tank/cylinder (for tank-to-combi conversions)
- Magnetic filter and system flush
- Building control notification and Gas Safe certificate registration
- Waste disposal of the old unit
At Boiler Services London, every quote is itemised up front, in writing, before we book a date. If something unexpected turns up on the day which does occasionally happen with older properties, we’ll always tell you and get your agreement before doing any extra work, not after.
Which Boiler Brand Should You Choose?
Brand affects both your upfront cost and how much you’ll spend over the boiler’s lifetime, so it’s worth understanding the trade-offs rather than just picking the cheapest unit price.
| Brand | Typical unit cost | Known for |
| Worcester Bosch | £1,800+ | Long warranty (up to 12 years), strong reputation in period properties |
| Vaillant | £1,900+ | Efficiency and smart controls |
| Ideal | £1,500+ | Value for money, reliable mid-range option |
| Viessmann | £2,000+ | Recommended for older/period housing stock |
| Baxi | £1,600+ | Widely available parts, straightforward servicing |
We’re an accredited installer for both Worcester Bosch and Vaillant, with warranties of up to 12 years available depending on the model. If you’re replacing an existing Worcester Bosch and want to understand your options before committing, our Worcester Bosch services page covers this in more detail, and our guide to Worcester boiler fault codes is useful if you’re currently deciding between repairing your existing unit or replacing it entirely.
Are There Any Grants Available in 2026?
Government support for heating upgrades exists, but it’s more limited for gas boilers specifically than a lot of online advice suggests:
- Boiler Upgrade Scheme (BUS): Offers £7,500 towards an air source heat pump or biomass boiler this grant does not apply to a straight gas-to-gas boiler swap.
- ECO4 Scheme: Can fully or partly fund a new boiler for households on qualifying means-tested benefits, regardless of boiler type, including gas.
- If you’re replacing a gas boiler with another gas boiler and don’t qualify for ECO4, there is currently no national grant available for the swap it’s worth budgeting on that basis rather than expecting a discount that may not apply to your situation.
How Long Does a Boiler Installation Actually Take?
A straightforward like-for-like swap is usually completed in a single day, including the survey, removal of the old unit, fitting the new one, and testing. Jobs requiring flue rerouting, gas pipework upsizing, or a full tank-to-combi conversion typically take one to three days, depending on how much additional work the property needs. Your engineer should be able to tell you which category your job falls into during the initial survey, not on the day itself.
Why Choose Boiler Services London for Your Boiler Installation
You’re trusting whoever installs your boiler with a job that affects your home’s safety and comfort for the next decade or more, so it’s worth being selective. Here’s what you get working with us:
- Gas Safe registered engineers, fully vetted and insured
- Up to 12-year warranty on installed boilers
- Accredited installer for Worcester Bosch and Vaillant
- Fixed, written quotes no surprise extras on install day
- 24/7 availability across Greater London
We cover installations across Tower Hamlets, Islington, Chelsea, Hammersmith, Brixton, Marylebone, Hackney and Kensington, plus the surrounding areas.
Ready to get a fixed, honest quote for your boiler installation? Call us now on 07877767776, or book your free survey online no obligation, no hidden extras, just a straight answer on cost and timing for your property.
Looking to fix rather than replace? Read our Worcester boiler fault codes guide. Already have a new boiler and want to keep it running well? See our annual boiler service page, or check our full FAQs for more on servicing, warranties, and costs.
Frequently Asked Questions
Fully fitted installations typically range from £1,800 to £4,500, depending on boiler type and the complexity of the job. A simple like-for-like combi swap is usually at the lower end.
Yes labour rates in London run roughly 20–30% above the UK average, which is the main driver of the higher quotes you’ll see compared with national price guides.
No planning permission is needed for a standard replacement, but the installation must be notified to Building Control (usually done automatically by your Gas Safe registered installer), and you’ll receive a Gas Safety Certificate on completion.
Only if you qualify for ECO4 based on income or benefits. The Boiler Upgrade Scheme’s £7,500 grant applies to heat pumps and biomass boilers, not gas-to-gas replacements.
A straightforward swap takes one day. Jobs needing flue rerouting or pipework changes typically take one to three days.