How much does a replacement boiler cost?

Time to replace a boiler? These are the things you need to know before you invest

The time to find a new boiler is never the right time. It's not all bad news though. A new boiler can be more efficient than older models. That means your replacement boiler cost may end up saving money in the long run thanks to a reduction in running costs. It could also be safer and mean you spend less on maintenance.

When the time is right to replace a boiler be sure to use a reputable installer to carry out the works. A cheaper deal isn't always the best option, especially when you consider that boilers need to last a long time to justify their cost.

‘When installed correctly by a competent professional, both gas boilers and heat pumps are very safe,' says Jamie Luck, sustainability consultant at Baltic Consultancy. 'Nearly all accidents are caused by installers not following the manufacturer’s instructions or third parties altering equipment they are not competent to.’ Going for a manufacturer chosen installer can often be the safest and easiest way to get a boiler installed, just not necessarily the most affordable, in the short term at least.

Insulation is also important to consider. ‘Small fixes can have huge impacts,' points out Keith Bastian, CEO of renewable home heating provider Fischer Future Heat. 'For example, fitting your hot water cylinder with an insulating jacket could save you £18 per year on your heating bill, and 110kg of carbon dioxide emissions.’

What do you need to look out for when thinking about replacement boiler cost? Read on to find out everything you need to know.

How much does a replacement boiler cost in 2023?

white boiler on green wall

(Image credit: YourHomeStyle)

The price of a new boiler isn't a single figure. You need to work out the replacement boiler cost based on a number of elements.

  • Decide what type of boiler you require, being a combi or storage boiler, for example.
  • Pick the brand and model that suits your needs and tastes. Some brands cost more up front, for example, but can have a longer lifespan and may work out more affordable in the long run. Another price factor to consider is the ongoing maintenance costs, where some brands may offer deals that include annual checks as part of the price.
  • Choose the size, which will vary, in kilowatts, based on the size of your home and its insulation levels. The bigger you go, the more the boiler is going to cost you both up front and in terms of running costs. This cost will extend longer term too if there are issues as the larger and more complex boilers can have more parts which will cost you more to repair and replace. If you insulate a home to its full potential, you may find that you can go for a smaller boiler which saves you money in the short and longer term. It also means a less wasteful and more eco-friendly boiler and home setup for you. ‘There’s little point heating homes for it all to escape via roofs, doors, nooks and crannies,' says Doug Johnson from Mesh Energy. 'So to ensure the rooms are warm and cosy the insulation needs to be optimised.’
  • Consider the cost of the boiler itself, the cost of installation and then any extra costs like extra radiators, pipework and structural work needed to make the boiler work in your setup.

Whenever dealing with boilers take this as an opportunity to check out your safety. Always ensure you have a working carbon monoxide detector, available on Amazon, nearby to monitor the air quality.

How much is a combi boiler replacement?

If you're replacing your current combi boiler with a new model, it should be a relatively straightforward installation process. If you're not changing location, only swapping out for a new boiler, you can expect to pay around £2,300 for the boiler itself and then the cost of labour and fittings to be a further amount of between £650 and up to £2,150. This is an estimated figure and can vary based on needs, but for most these amounts this replacement boiler cost for a combi should cover the average UK home.

You will also need to factor in the work related to the boiler type, such as removal of old tanks and new pipework. Also consider the potential need for a new space to be made to house the boiler. But more on these extras costs further down this guide.

How much is a system boiler replacement?

A system boiler, which uses a tank to keep hot water, is designed for larger homes requiring a constant supply of hot water across the property. In this case, there is more space needed and more parts to replace. Presuming you only need to change the boiler unit itself, the replacement boiler cost can be relatively straightforward. The water-cylinder itself can cost between £900 and £1,300 depending on the capacity.

For a direct boiler replacement, in the same space as before, the boiler itself starts at £2,500 and then costs for labour and parts can be between £650 and £2,150 depending on your home.

digital thermostat on grey wall

(Image credit: Wunda)

How much does it cost to replace one type of boiler with another?

A common upgrade is to go from a system boiler with an older tank to a more efficient combi boiler. But you may find the need to replace a heat-only boiler with a combi or system boiler, for example. In the case of replacing an older combi boiler with a new system boiler the cost is likely to range from £1,850 to £4,100 for labour and parts with the boiler system itself starting from £3,400.

Going from a heat-only boiler to a new system boiler will once again be from £3,400 for the new boiler setup and installation can range from £1,550 up to £3,450. All costs are a guide and can vary based on your property size, the boiler you go for and the types of extras layers to the installation job any property can create.

How much does it cost to replace a regular system boiler with a combi boiler?

As mentioned above, if you want to replace an older system boiler with a combi boiler that will mean removing the old water tank. This could get you back a mass of cupboard space but removal of the tank and any unsightly, no longer used pipes can cost you in labour and waste disposal charges. The combi boiler itself will also require specific piping installation to replace the older unit with the new model.

A new combi boiler starts from £2,500 and increases based on the power output that your home needs. Installation should be from £950 to £2,800. So that's a total minimum replacement boiler cost of £3,450.

How much does it cost to replace a back boiler with a combi boiler?

A back boiler, which uses a property's fireplace to heat water for the home, was something found in the 1960s, Seventies and Eighties. If you're planning to get rid of the fireplace and want to save space by putting your new combi boiler in there, a straight swap out could be a good option – but it's likely elsewhere will better suit your pipeworks and access.

A new combi boiler will cost you from £2,500 and the installation can vary based on the removal work. This can mean removing the chimney to get access to the old back boiler. If you're installing elsewhere, this could be left and potentially could save you installation fees. Expect to pay from £950 to £2,150 in installation costs.

white Homeserve boiler on grey wall

(Image credit: Homeserve)

What could affect the cost of my replacement boiler?

Here are the factors to consider around replacement boiler cost:

1. Your pipework needs replacing

When you swap out a boiler location or type it's more than likely that you'll need new pipework. This not only means you need to consider the cost of the piping itself (copper in most cases), but also the cost of removing the older pipes and disposing of them. 

This price varies widely as the amount of piping can change from job to job. But with labour inclusive you can expect to pay from hundreds of pounds to up to around £1,000. This price does include the removal of the old boiler and disposal of that too.
Estimated cost added: £300 to £1,000

2. You need to reposition your boiler

By moving your boiler it means moving pipework as well. In some cases it can also mean construction work – dealing with walls, floors and even making cupboards. As such the price varies but you can expect a simple boiler reposition to start at around the £500 mark, including getting rid of the old unit and pipework. It can go over the £1,000 mark quite easily as that distance increases and the job gets more complicated.
Estimated cost added: £500 to £1,200

3. The flue position

You may find that you need a new vertical flue, especially if you're moving your boiler's location. This can vary in cost but typically is between £300 and £600. This large pipe, which leads outside of your home makes sure condensation and gases are piped safely away from your property. 

These flues usually leave the home horizontally and that will be included in the cost of installation. But in some cases they need to leave vertically, due to the space provided, which is where these extra costs can appear. Estimated cost added: £300 to £600

4. You buy an additional warranty

Getting an extended warranty is a good idea when it comes to boilers, especially if you can get a 10-year one. Since that is the life a boiler is expected to last, less if not looked after and more if well cared for, it's a useful support to have in place. A decent additional warranty can be found by trusted partners of manufacturers so be sure all the correct paperwork is in place. Some may require additional hardware fitted, like a magnetic boiler filter, which can cost you upfront but can also ensure the longer life of your boiler, saving you in the long run.
Estimated cost added: £150 to £250

5. You want to add smart heating controls

Smart heating controls are more common than ever now which means they're also more affordable and work better than ever. These allow you to connect your heating system to your home's internet. This means, using an app on your phone, you can control your heating from anywhere that you find yourself – presuming you have an internet connection there.

Set timers, fire up the heat as you're driving home and make sure your pipes are safe when away over cold winters. There are a selection of brands available now and you'll likely find your installer specialises in one or the other. If you're already integrated with Google then the Nest, available on Amazon, is a good option, but if you want multi-floor and even thermostatic individual room controls then Hive, also available on Amazon, is better suited. Estimated cost added: £100 to £300

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Luke Edwards

As a veteran tech journalist of over two decades, Luke knows what makes a gadget tick but is also well aware of what you want to read about when doing your research.  He has worked in this world for over 20 years and loves testing, reviewing and working with brands on new gadgets. Not only does this mean he's got plenty of experience reviewing tech, but that he is in a good position to see how trends have appeared and caught on or been left by the wayside. As such he consults for many tech companies helping them create new gadgets. All that adds up to words which you can expect to give you clear guidance on what's worth investing in, to upgrade your home and your life for now and the future. Expect concise words on everything from smart home tech and power tools to solar panels, cars, smartphones, speakers and plenty more besides.