How Much a New Boiler Costs In London (With Installation)

A boiler on a blue wall

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August 7, 2023

If you’re considering replacing your current source of heating and hot water and wondering how much a boiler costs, then read on. In this guide I talk about not just the cost of a boiler replacement, but the different boiler models available.

We’ll get more in-depth too, talking about the various parts involved, as well as how much you should expect to pay for installation.

We’ll also discuss whether or not it’s best to swap from your current boiler type to another, and what to expect when you do. And what about relocating your boiler to another part of the house? Yes, you’ve guessed it – we’ve got that covered too. Read on to find out…

Average Costs of a New Boiler in London

When it comes to purchasing a new boiler there is a huge number of variables involved. That’s why, when you’re wondering “how much does a new boiler cost”, be prepared to be quoted sums in the range of £600, all the way up to £4,000.

The variables include the type of boiler you want, whether it’s gas or oil and who the manufacturer is. It also depends on whether you are changing from one type of boiler to another. In this scenario, you’ll need new pipework and you may need another new water cylinder or cold-water tank – and to have previous tanks removed.

It may be that you want to change the current location of your boiler. In which case, expect to pay more for the new boiler installation. Labour charges for installing the boiler also vary, depending on where you live (London fitter costs being far more expensive than in other areas of the UK).

Other costs can come down to the need for additional parts, such as Thermostatic heat controls, a magnetic filter, a system power flush or a new boiler flue pipe.

Boiler Prices

A standalone boiler replacement can cost anything from £600 up to £3,000. The cost depends on what type of boiler you plan on buying, and who the manufacturer is.

Boiler and Installation

A boiler installation cost quote usually involves the price for fitting too. In other words, you’re paying for the material and labour in one go.

Boiler Conversion

A boiler conversion always costs more than a standard replacement boiler. That’s because there is so much more work involved.

New Boiler in a New Area of the Home

When you want to change the location of your existing boiler, things get a bit more complicated. You can also expect to pay around £600 more for the job, depending on where you’re moving the boiler to. If it’s a move next door ie from the bedroom to the kitchen then it’ll cost around £200. But, if you’re taking it upstairs to a new loft extension then you’ll pay three times that amount to relocate the boiler.

That’s because there will be the cost of new fittings and fixtures to consider, together with additional pipework. There will also be many more hours of labour involved. As such, it’s usually best to keep the location of your existing boiler.

Having said that, if you’re changing from a back boiler to a combi then you’ll certainly have to remove the back boiler. It’s actually against the law to install a back boiler these days so any existing back boilers must be replaced with either a combi boiler, a regular boiler or a system boiler.

A close up of the controls on a boiler

Boiler Costs Breakdown

When having a boiler fitted there is the cost of the boiler itself – a new combi boiler will cost from £500-£3,000. Then you’ll pay for the labour and any additional parts required (£1,000-£3,000).

The Boiler

If you’re wondering how much a boiler replacement costs then there are five main types householders are interested in these days.

The least expensive is the combi boiler which, including installation, has an average cost of £2,750. Next is an electric boiler, averaging £2,790.

A system boiler will set you back approximately £2,790 while a conventional boiler is around £2,955 on average for materials and fitting.

Finally, the eco-friendly Biomass boiler will set you back around £16,000.

Combi Boiler Costs (Combination Boilers)

Purchasing a combi boiler these days can cost anything from £1,800 up to £4,000. The more complicated the installation, the more money you’ll have to pay.

The ‘combi’ in ‘combi boiler’ is a shortened version of the word ‘combination.’

It gets its name from the fact it controls both the heating and hot water in your home. Both are provided ‘on demand’ ie the system doesn’t have to heat up the water or pipes first. This makes it much more efficient than an immersion heater.

System Boilers

A regular (or system boiler) has a separate water cylinder (usually found in an airing cupboard) and/or a water tank (usually in the loft). You won’t get instant hot water with this type of boiler. It’s the best type of boiler for those with large families because of the higher than usual demand for hot water.

The cost of a new regular boiler starts at around £1,500 and goes all the way up to £3,000. Again, this depends on who the boiler manufacturer is, how complex the job is and whether or not you’ll need additional pumps or valves etc.

Regular Boilers (Conventional)

Best for big families, a regular boiler (also known as a heat only boiler) is the traditional boiler of yesteryear. The boiler is supported by a cold-water tank and hot-water cylinder.

Electric Boilers

Electric boilers are regarded as the environmentally-friendly option when you’re having your heating and hot water supply upgraded. Certainly, some have up to 100 per cent efficiency ratings.

The boilers don’t release any toxic gases into the nearby environment, nor carbon. Having said that, the electricity the majority of electric boilers run on is mainly generated by burning gas. Only if you choose one of the renewable energy providers, such as Octopus Energy, will you avoid this.

Electric boilers tend to be smaller than other types of boilers. Because they don’t run on gas they tend to be more expensive and they’re not great for larger householders in terms of providing enough hot water on demand etc.

You can expect to pay anything from £600 to £3000 for the installation of a new electric boiler.

Oil Boilers

Less common than a gas boiler, an oil boiler has an oil tank nearby in which it stores fuel. The oil is ignited in a combustion chamber and warms up cold water via the heat exchanger.

If it’s a combi system that’s being used this is done from the mains. If it’s a conventional system then it’s in the hot water tank. The hot water is then distributed to the shower, radiators etc.

A condensing oil-fired boiler is usually at least 90 per cent efficient. Oil is also more efficient than gas as there’s less wastage.

This type of boiler costs anything from £600 up to £2500.

Biomass Boilers

Similar to a conventional gas boiler, your biomass boiler uses sustainably sourced wood pellets to fire itself up. These are produced from reused materials and are actually carbon neutral so great for helping the government reach its Net Zero target halfway through this century.

Are you wondering how much a boiler costs when it’s this energy efficient and eco-friendly? Well, this new technology will set you back anything from £7000 up to £15000.

Labour Costs

A straightforward swap from an old boiler to a new boiler of the same type ie combi to combi will cost up to £800 in labour charges.

If the installation is more complicated and involves swapping between different types of boilers ie from a back boiler to a combi, then you can pay as much as £1500 in labour costs (more if you live in London or a very remote location).

Heating Controls & Thermostat

Expect to pay anything from £30 for a basic thermostat up to £300 for a smart version such as Hive or Nest. Not only do the latter switch off your boiler on command, but they can also give you updates on how much energy you’re using and therefore how much you can expect to pay.

Vertical Flue

A large piece of pipe that leads from the boiler to the outside, your vertical blue can cost from £50 up to £500. A necessity for any boiler, the flue ensures all gases and condensation deriving from the boiler are pumped outside into the atmosphere (rather than into your kitchen or other areas of your home).

Most flues are horizontal and cost at the lower end of the scale. The higher prices come in when you need a vertical flue.

Plume Kit

An extension allowing the flue to be attached to your boiler, the plume kit is used when the boiler flue is too close to a door or window, or even a neighbouring property. Expect to pay anything from £75 to £150 for this piece of kit.

Chemical Flush

A chemical flush is similar to a deep clean for your heating system. It is used to remove any sludge from radiators (which prevents the hot water from flowing through easily).

You can tell one is required if the radiators are cold at the bottom and warm at the top. A hot chemical flush can cost from £50 up to £150.

If a power flush is required you could end up paying out around £500. These aren’t recommended for older systems though, due to the strength involved.

Magnetic Boiler Filter

A magnetic boiler filter is installed on the pipework to help protect your new boiler. It works by trapping small particles of metal and dirt so they don’t enter the boiler itself where they may cause damage. You can expect to pay anything from £100 to £200 for this.

Gas Pipe Upgrades

If your pipes are old and need replacing or you are changing boiler type then you’ll probably need to have extra piping installed. Copper piping isn’t cheap, coming in at around £300.


The hot water from the boiler flows through your radiators to warm up your home. Prices for radiators vary enormously, from £40 for a basic version up to more than £1000 for a large, designer radiator.

A radiator

Why is There a Huge Variation in Costs?

Start researching boiler installation costs are you’ll notice a huge variation between companies. That’s why it’s always a good idea to shop around and see if you can get the best deal. It’s certainly sensible to get more than one quote – three is typical.

How much a boiler replacement costs will vary depending on the type of boiler you choose and whether or not this is the same as your previous boiler. If not, the price will increase as there will be more work involved. The same goes for changing the location of your boiler.

Expect to pay anything from £500 to £3500 for installation costs – before you’ve even purchased the boiler.

Boiler Brands

The main boiler brands here in the UK are Worcester Bosch, Vaillant, Viessmann, Ideal, Alpha and Baxi. But there are others too, which you can see below:

Worcester Bosch

One of the main players in the boiler industry in the UK, Worcester was set up in the 1960s and acquired by the Bosch Group in 1992. Environment 2000 is their award scheme recognising environmentally friendly installations.

The company sells gas and oil boilers, in the form of combi, regular and system designs.


Vaillant started life back in the late 19th century as a pump maker. By 1999 it had sold more than 40 million boilers. The Vaillant Group Gmbh was formed in 2012. It is main production sites are in Germany, the UK and other European countries. Vaillant Group have implemented a Sustainability in Environment, Employees, Developments and Products and Society (SEEDS) strategy.

Valiant provides combi boilers, system boilers and open vent (heat only) boilers.


A British company which has been around for more than a century, Ideal provide boilers for residential and commercial customers. They supply a range of boilers, from combi to system and heat-only appliances.


Another British company, Baxi has been around for nearly 200 years. It was founded by Richard Baxendale back in 1825 but today is part of the BDR Thermae group. That makes it one of the largest boiler manufacturers in Europe. It is Baxi Duo-Tec Combi HE won the CORGI boiler of the year back in 2008. The company produces biomass, combination and heat-only boilers.


Founded in 1917 by German entrepreneur Martin Viessmann, the company now has more than 11,000 employees scattered in 11 countries throughout the world. It deals mainly in a gas combi boiler.


A British company, Glow-worm has been supplying boilers for more than 90 years. Their Derwent Foundry in Derbyshire was founded back in 1934 and remains in Belper to this day. Glow-worm was acquired by the Vaillant Group back in 2001, meaning its now part of the second-largest heating company in Europe. They supply combi and system boilers.


Thomas Potterton invented the ‘Zig-Zag’ boiler in 1894. His sons took over the business, continuing to produce new boiler products, and even supplied No 10 Downing Street at one time. Based in Warwick, they launched a popular gas-fired and ‘DOA’ oil-fired boiler series in 1955. The business changed hands over the years and today the owners are Baxi.

Alpha Heating Innovation

A company that has been producing boilers for more than half a century, Alpha Heating Innovation operates in the UK. Today it’s part of the Italian company Immergas, where it’s the largest supplier. It operates in more than 30 countries around the world.


Based in Walton-on-Trent, Derbyshire, Ferroli began life in Verona Italy after founder Dante Ferroli began business in 1955. It began in the UK in the 1980s and today operates in 12 countries, producing both energy-saving domestic and commercial boilers, together with renewable energy products. Produces condensing combi and systems boilers as well as electric boilers.


Founded in 1978, Grant launched it is first back boiler a couple of years later. The Wiltshire-based company produced more boilers over the years, included oil-based and combi versions. Today they produce an eco-boiler alongside other energy-efficient products, such as heat pumps, solar panels and underfloor heating.


Around since 1939, after half a century, Intergas were famous for their high-efficiency condensing boilers. A Dutch company, they have been around in the UK since 2008 when they opened in the Midlands.

In 1996 the company came up with a boiler component known as their bithermic heat exchanger. This is for their condensing combi boiler and which allows it to condense continually in both hot water and central heating modes, making it more energy efficient. Today the company produce other low emission solutions for heating and hot water.


Part of the Vaillant Group, Heatline has been manufacturing heating equipment for more than half a century now.  Their latest innovation is the Capri Plus range of condensing combi boilers.


Glasgow-based Vokèra was established more than 35 years ago. It manufactures domestic and commercial gas boilers, as well as air source heat pumps, unvented cylinders, water heaters and solar thermal collectors. Its parent company is Riello Group, which in turn is owned by Carrier. Vokera produces combi, system and open vent boilers.


Founded in 1987, Ravenheat is an independent boiler manufacturer based in Leeds. There are also two manufacturing plants in Verona, Italy. The company first started producing condensing boilers back in 1996. Their Ravenheat OpenTherm boiler operates in an energy-efficient condensing mode.


Boasting more than 90 years in the heating market, Ariston Boilers was founded in the 1930s. It wasn’t until the 1960s though that they first brought electric water heaters and gas cylinders onto the UK market. They grew quickly in Italy and by the 1980s were producing their own boilers for UK households. They have since acquired many other companies and in 2009 rebranded as Ariston Thermo.

Is It Worth It? Potential Savings for a New Boiler

There is no doubt that, if you can afford it, having a new boiler fitted will save you money on your energy bills. That’s because it will be so much more efficient.

In other words, you’ll recoup most of the cost of it over its lifetime by passing less utility costs than you would have previously (were the tariffs the same). These days, with escalating energy bills it’s more important than ever to have an efficient boiler system.

As an example, the Energy Saving Trust estimates that changing from a G-rated gas boiler to a new A-rated condensing boiler with a thermostat as well as controls can result in a household saving of nearly £600 per year if you live in a detached house.

It works out at £380 for a semi-detached home, while if you live in a flat you can look forward to saving around £150 annually.

Government Grants for New Boilers

The UK government provide several grants for homeowners looking to replace their older, inefficient boilers. It makes perfect sense, considering the escalating cost of utility bills in recent times. But that’s not the only reason the government is urging home and business owners to upgrade. There’s also the Net Zero target by 2050.

There are two main grants – the ECO4 set and the Boiler Upgrade Scheme. To be eligible, recipients have to meet certain income and health criteria. We outline what both entail here:

ECO4 grants

These are grants aimed at paying for energy-efficient improvements, such as boilers, insulation (for lofts and cavities), electric storage heating and air source heat pumps.

Low-income households who are also amongst the least energy efficient will benefit from the grants. That means those who are currently on benefits and whose homes fall into the D-G energy efficiency banding.

As part of the ECO4 grants, the LA Flex Funding Scheme gives big discounts on home insulation to households whose finances are a struggle. The ECO4 grants scheme is open until 2026.

Boiler Upgrade Scheme

The boiler upgrade scheme means the government will give property owners in England and Wales, £5,000 off the costs of a biomass boiler or an air source heat pump. There’s £6,000 available for a ground source heat pump. The money is to encourage householders (or owners of small non-domestic properties) to install low-carbon heating. The scheme runs until 2025.

Warm Nest Wales

Householders (including private sector tenants) can get help with energy improvements. This includes replacing the boiler to a more efficient system, as well as funding for insulation and solar panels.

Warmer Homes Scotland

Boiler replacements and other energy-saving improvements are paid for by the Scottish Government if their assessment gives the go-ahead. Like in Wales, this scheme is open to private sector tenants.

Boiler Replacement Scheme, Northern Ireland

The government in Northern Ireland will give funding from £400 up to £1000 for the cost of a boiler replacement, depending on the household’s income.

Finding Someone to Install Your Boiler

Now that you’re equipped with far more knowledge about what your boiler installation entails and just how much you can expect to pay, it’s time to find a boiler fitter (or heating engineer).

Let The Page curate you a free bespoke shortlist of tradespeople suited to you and your job.

There are a handful of ways you can do this, such as:

  • The Page – You’ll find plenty of expert boiler installation engineers on The Page. Simply send us an enquiry and we will match you with a curated list of trusted traders.
  • British Gas – they will install a boiler for you but can often be more expensive.
  • Online DirectoriesTrustMark and Buy with Confidence are two online directories which are government and local authority-run respectively. Members are vetted, have insurance and adhere to a code of conduct. There are also complaints procedures.
  • Ask Other People – Friends, family and work colleagues can often come up with the name of the company or individual who installed their boiler. If they’re happy with the service, they’ll give you a recommendation.

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