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25 October 2021

How much does a new boiler cost?

Find out how to get a new boiler installed and how much it should cost. We'll help make sure you don't get overcharged for your boiler installation
SM
Sam Morris
How much does a new boiler cost?
How much does a new boiler cost?

Boiler installation costs vary enormously, depending on how much work is required, the parts needed, their availability and even where you live.

Read on to find out how much you should expect to pay for a new boiler installation

To make sure you're getting the right model for your home, read our how to buy the best boiler guide. 

Or, if you're struggling to meet the cost of a new boiler, find out whether you're eligible for a free boiler or boiler grant

The cost of a new boiler

The price you pay for a new boiler will vary depending on:

  • The type If you're getting a heat-only or storage boiler, there may be extra costs if you need a hot water cylinder fitting.
  • The brand/model Although most boiler brands offer models at different price points, some brands are cheaper overall. Getting a reliable boiler is the most important thing to consider when deciding which brand to go for as it will save you money and stress in the long run.
  • The size The larger the boiler (in kilowatts) the more expensive it usually is.

To give you an idea of current boiler prices, in the table below we've complied what you can typically expect to pay for the different types of boiler. 

The price for a boiler can vary depending on the model, its size and the price your engineer can get the boiler for. However, our analysis should give you a sense of typical costs. Contact a boiler manufacturer directly for its latest prices and offers.

If you're a Which? member, you can log in now to unlock the tables. If you're not a member, try Which? today.

Type of boiler
Average price
Price range
Gas combi
Gas heat-only
Gas system
Oil combi
Oil heat-only
Oil system
Last updated September 2021

Average price Based on the average price of boiler, per type, for all boiler models on which.co.uk as of September 2021. Price range is the highest and lowest price based on all boiler models on which.co.uk as of September 2021.

Not sure what type you should get for your home? Read our guide to different types of boilers for the pros and cons of each

Boiler installation costs

The cost of the installation will include the price of the new boiler, a system clean and labour, plus any additional extras you want.

Depending on the amount of work the engineer needs to do to fit the boiler will affect overall costs - for example, if the installer needs to change pipework or alter the location, then you should expect labour costs to be higher.

It's important to get your heating system cleaned when getting a new boiler installed to remove any built-up sludge, which makes sure your heating system remains as efficient as it can be. There are different methods of cleaning a heating system. A power flush, used to clean heavily sludged systems, typically costs £350 according to Checkatrade

If you haven't already, we'd recommend that you consider adding a magnetic filter to your heating system. A filter keeps your system free of gunk long after the heating engineer has left. Magnetic filters cost between £70 and £130.1

Thermostatic radiator valves (TRVs), can also be an effective way to keep your system balanced and room temperatures comfortable. They can also lead to lower heating bills if used correctly as they can prevent rooms you don't use very often from being overheated. They cost around £15 each and you'll need one per radiator.

You could also consider getting a smart thermostat and/or smart radiator valves as they allow you to control your heating remotely through a smartphone or tablet, set heating schedules and could lower your heating bills even further. 

The prices of smart heating devices vary depending on the brand and features each product offers, but you can typically expect to pay between £100 and £250 for a smart thermostat, and £50 to £80 per smart radiator valve.

Delta-EE have carried out an independent analysis, on behalf of the Department for Business, Energy & Industrial Strategy (BEIS), on the cost of installing different heating measures. This looked at various scenarios for boiler installations, reporting the typical costs associated with them.

For larger boilers (above 30kW), a bigger gas supply line may be needed between the gas meter and boiler to make sure the pressure drop isn't too large. If you're replacing a boiler smaller than 30kW for one that is larger than 30kW, you may have to pay between £100 and £300 for a bigger gas supply line.2

Replacing a heat-only or system boiler with a combi model will require additional labour and re-piping, typically costing an extra £300 to £650.2

If you're replacing combi boiler with a heat-only or system model, you'll likely need to install a new hot water water cylinder. This can range from £300 to £600 for a vented cylinder (connects to a cold water tank) to £900 to £1,300 for an unvented cylinder (connects directly to the mains), depending on the cylinder's size and how well insulated it is.2

As a rule of thumb, if you're directly swapping like for like, you can expect the overall cost to be lower than if you're changing the type of boiler in your home or relocating it.

Combi boiler installation costs

Combi boilers are great for smaller homes or flats that typically have one bathroom. A combi boiler heats water on demand and doesn't require a large hot water cylinder or feed tank.

We've combined the findings from the Delta-EE report with our boiler pricing in the table below to give you a rough price range (with an average price in brackets) for what you should expect to pay for different combi boiler installations.

Only Which? members can log in to unlock the tables and find out how much you should expect to pay to install a new combi boiler. If you're not a member, try Which? today and you'll get access to the prices we would expect an engineer to charge for installing a combi boiler.

Scenario
Cost of boiler
Cost of labour, fittings and additional parts/fees
System clean
Total cost (excluding VAT)
Replacing a combi boiler with a new combi, in the same location
£650 to £2,150
(£1,200)
Replacing a heat-only or system boiler with a new combi boiler
£950 to £2,800
(£1,700)
Last updated September 2021. Average price shown in brackets.

Cost of boiler Based on all boiler models on which.co.uk as of September 2021. Cost of labour/fittings and additional parts/fees Based on values from the Delta-EE report.2 Low values representative of installations where boilers are easy to remove, most of the old fittings can be used and easy to access the building. High values are representative of complex installations where boilers are difficult to remove, lots of fittings need replacing/boiler needs relocating and the building is difficult to access. Additional parts/fees (when applicable) includes extra parts, such as the cost of a new hot water cylinder and extra costs for swapping a non-combi for a combi boiler. System clean Based on 2019 research by Which? with the Association of Plumbing and Heating Contractors.

If you want a new combi boiler, make sure you read our combi boiler reviews so you buy the most reliable brand

Heat-only boiler installation costs

Heat-only, or regular, boilers require a hot water cylinder, usually in an airing cupboard, plus a cold water feed tank typically found in the loft. The two tanks means they're most suitable for larger homes.

Because the hot water they produce is stored in a cylinder, they can provide a large amount of hot water to many taps at the same time – ideal if you have a big family or multiple bathrooms. 

If you don't already have a hot water cylinder in your home or wish to replace an existing one, this can cost from £300 for a lower-capacity and poorly insulated cylinder up to £600 for one with a higher capacity and that's highly insulated (BEIS report, 2020).

We have combined the findings from the BEIS 2020 report, for labour costs and fittings, with our boiler pricing in the table below to give you a rough price range (with an average cost in brackets) for what you should expect to pay for different combi boiler installations.

Only Which? members can log in to unlock the tables and find out how much you should expect to pay for your heat-only boiler replacement. If you're not a member, try Which? today and you'll get access to the prices we would expect an engineer to charge for installing a heat-only boiler.

Scenario
Cost of boiler
Cost of labour, fittings and additional parts/fees
System clean
Total cost (excluding VAT)
Replacing a heat-only boiler with a new heat-only boiler in the same location (no new hot water cylinder)
£650 to £2,150
(£1,200)
Replacing a heat-only  boiler with a new heat-only boiler in the same location (including a new vented hot water cylinder)
£950 to £2,750
(£1,700)
Replacing a combi boiler with a new heat-only boiler (including a new vented hot water cylinder)
£1,250 to £3,400
(£2,200)
Last updated September 2021. Average price shown in brackets.

Cost of boiler Based on all boiler models on which.co.uk as of September 2021. Cost of labour/fittings and additional parts/fees Based on values from the Delta-EE report.2 Low values representative of installations where boilers are easy to remove, most of the old fittings can be used and easy to access the building. High values are representative of complex installations where boilers are difficult to remove, lots of fittings need replacing/boiler needs relocating and the building is difficult to access. Additional parts/fees (when applicable) includes extra parts, such as the cost of a new hot water cylinder, and extra costs for swapping a non-combi for a combi boiler. System clean Based on 2019 research by Which? with the Association of Plumbing and Heating Contractors.

If you're looking for a new regular boiler, also known as a heat-only model, make sure you check our regular boiler reviews

System boiler installation costs

A system boiler is just like a regular boiler, except that it doesn't need a large cold water feed tank for operation. As such, the hot water cylinder needed for a system boiler is an unvented one (sometimes called 'closed vent' or 'sealed'). These typically cost £900 for a for a lower-capacity and poorly insulated cylinder up to £1,300 for one with a higher capacity and that's highly insulated (BEIS report, 2020).

We've combined the findings from the BEIS 2020 report, for labour costs and fittings, with our boiler pricing in the table below to give you a rough price range (with an average cost in brackets) for what you should expect to pay for different combi boiler installations.

Only Which? members can log in to unlock the tables and find out how much you should expect to pay for your heat-only boiler replacement. If you're not a member, try Which? today and you'll get access to the prices we would expect an engineer to charge for installing a heat-only boiler.

Scenario
Cost of boiler
Cost of labour, fittings and additional parts/fees
System clean
Total cost (excluding  VAT)
Replacing a heat-only or system boiler with a new system boiler in the same location (no new hot water cylinder)
£650 to £2,150
(£1,200)
Replacing a heat-only or system boiler with a new system boiler in the same location (including a new unvented hot water cylinder)
£1,550 to £3,450
(£2,200)
Replacing a combi boiler with a new system boiler (including new unvented hot water cylinder)
£1,850 to £4,100
(£2,700)
Last updated September 2021. Average price shown in brackets.

Cost of boiler Based on all boiler models on which.co.uk as of September 2021. Cost of labour/fittings and additional parts/fees based on values from the Delta-EE report.2 Low values representative of installations where boilers are easy to remove, most of the old fittings can be used and easy to access the building. High values are representative of complex installations where boilers are difficult to remove, lots of fittings need replacing/boiler needs relocating and the building is difficult to access. Additional parts/fees (when applicable) includes extra parts, such as the cost of a new hot water cylinder, and extra costs for swapping a non-combi for a combi boiler. System clean Based on 2019 research by Which? with the Association of Plumbing and Heating Contractors.

Head to our system boiler reviews if you're looking for a new system model.

Oil boiler installations

Installation of the following oil systems should be carried out by a trained professional:

  • An oil-fired combustion appliance, which has a rated heat output of 100kW or less, and which is installed in a building with no more than three storeys (excluding any basement) or in a dwelling
  • Oil storage tanks and the pipes connecting them to combustion appliances
  • Heating and/or hot water service systems connected to an oil-fired combustion appliance

Several schemes, listed below, exist to help you track down a suitable person for oil appliances. You can find more details on these websites:

Like gas boilers, you can expect lower installation costs if you're directly swapping your current oil boiler for a similar model. If you're swapping the type of boiler, relocating where your oil boiler is or needs a lot of old fittings replacing, then the costs will increase.

Additionally, you may have to install an oil store (including piping from the store to the boiler). Smaller oil stores, suitably for smaller boilers and houses that have easier access to oil supplies typically cost around £1,300. If your home has a larger oil boiler, or is in a remote location where you'll want a larger store to ensure you have a fuel supply, this will cost around £2,400 (BEIS report, 2020).

We've combined the findings from the BEIS 2020 report, for labour costs and fittings, with our boiler pricing in the table below to give you a rough price range (with an average cost in brackets) for what you should expect to pay for different combi boiler installations.

Only Which? members can log in to unlock the tables and find out how much you should expect to pay for your heat-only boiler replacement. If you're not a member, try Which? today and you'll get access to the prices we would expect an engineer to charge for installing a heat-only boiler.

Scenario
Cost of boiler
Cost of labour, fittings and additional parts/fees
System clean
Total cost (excluding VAT)
Replacing a combi oil boiler with a new combi oil boiler in the same location
£800 to £2,300
(£1,200)
Replacing a combi oil boiler with a new heat-only or system oil boiler (including a new hot water cylinder)
£1,100 to £3,600
(£1,950)
Replacing a heat-only or system oil boiler with a new heat-only or system oil boiler (no new water cylinder) in the same location
£800 - £2,300
(£1,200)
Replacing a heat-only or system oil boiler with a new combi oil boiler
£1,100 to £2,950
(£1,700)
Last updated September 2021. Average price shown in brackets.

Cost of boiler Based on all boiler models on which.co.uk as of September 2021. Cost of labour/fittings and additional parts/fees Based on values from the Delta-EE report.2 Low values representative of installations where boilers are easy to remove, most of the old fittings can be used and easy to access the building. High values are representative of complex installations where boilers are difficult to remove, lots of fittings need replacing/boiler needs relocating and the building is difficult to access. Additional parts/fees (when applicable) includes extra parts, such as the cost of a new hot water cylinder, and extra costs for swapping a non-combi for a combi boiler. System clean Based on 2019 research by Which? with the Association of Plumbing and Heating Contractors.

Head to our oil boiler reviews if you're looking to get an oil boiler installed

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Why a reliable boiler is important

Although it depends on the faulty part, on average it costs £200 each time a boiler needs fixing.3 With that in mind, it doesn't take long for repair costs to stack up and that's not accounting for the inconvenience of days without heating and hot water. 

In our 2021 survey, we asked 8,001 members of the general public, who had bought a boiler in the past six years, when their boiler needed it's first repair (if it's needed one at all). 

The graph below shows the percentage of boilers that remain fault-free in the first six years after installation. The least-reliable brand is about twice as likely to develop a fault as the most reliable. 

Over the course of your boiler's life, a reliable boiler brand will save you money compared with going for a less reliable one. Our survey findings show that it isn't just the biggest boiler brands that are reliable – you can get more affordable boilers from companies with great reliability. 

Read our best gas and oil boiler brands guide to discover the most and least reliable brands

Finding a registered boiler installer

You should always get a gas boiler installed by a gas safe-registered engineer. The Gas Safe Register provides details of registered installers in your area. Alternatively, call Gas Safe on 0800 408 5500.

Each installer must carry an ID card, which lists the gas work they're qualified to do.

Which? Trusted Traders are vetted heating enginners who are all gas safe registered. As such it should be your first port of call for finding a registered boiler installer.

Before you call an installer, make sure you've got a good grounding in what to expect when you get a new boiler. Check out our how to buy the best boiler guide. If you're unsure what type you need, take a look at our guide to different types of boiler.

You can use our Which? Trusted Traders search tool below to find a reliable local tradesman near you, you don't have to be a Which? member to use Which? Trusted Traders.


Based on the low and high prices of central heating filters available on screwfix.com as of September 2021

Delta -EE report for the Department for Business, Energy and Industrial Strategy 'The cost of installing heating measures in domestic properties' (2020)

May to June 2021, Which? reliability survey of 8,001 members of the public who'd bought a boiler in the past six years.