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Replacing your boiler - full guide

We explore boiler costs, tips on choosing a new boiler and what to expect during the installation.

Already know how to replace your boiler? Why not get a new boiler with us?

Do you need to replace your boiler?

Before we dive into the nitty-gritty of boiler replacement costs, consider first whether you really need to replace your boiler. Has it stopped working or is there a fault that can be repaired? If there’s a leak or the boiler pressure has changed, you might be able to fix it yourself.

How often should I replace my boiler?

Most people in the industry expect a boiler to last 10-15 years – assuming it’s been looked after and serviced regularly. So you shouldn’t need to replace your boiler more often than this.

If your boiler is only a few years old and something goes wrong, check whether it’s still covered by the manufacturer’s warranty. If it’s the first time a fault’s occurred, read our 10 common boiler problems to see if you can fix the fault yourself. If not, get it repaired by a qualified engineer.

couple standing next to boiler

How do I know I need to replace my boiler?

Generally, there are some clear signs that indicate it’s time to replace your boiler:

  • Calling out an engineer to fix the boiler more than once a year
  • Replacing parts is getting expensive and/or they're hard to find
  • You've extended your home and it's not as warm as it used to be before the refurb
  • Higher energy use on your bill even though you haven't changed your lifestyle - older boilers are less energy efficient 

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Save more than £300 when you replace your boiler

Perhaps you’re renovating your home and want to invest in a more energy-efficient heating system. So that you can enjoy a warmer home and hot water without spending more on your heating. The Energy Saving Trust estimates that families in a detached house can save up to £315 a year by upgrading from a G-rated boiler to a new A-rated condensing boiler. 

Read more about boiler efficiency in this guide from our boiler partner, BOXT.

Do I need to replace my boiler with the same model?

There are all types of boilers available – and you don’t have to replace like-with-like. In fact, it’s best to review your options afresh, because modern boilers are far more efficient.

For instance, if you had a non-condensing boiler before, your new gas boiler is likely to be a condensing model, since these became law from 2005. Their design means they don’t lose as much heat as non-condensing boilers. So they won’t cost as much to run. Read more about the main types of boilers in this guide.

How much does a new boiler cost?

The cost to replace a boiler varies enormously – starting anywhere from £1,500 up to more than £3,000 but it depends on a number of things:

  • The size of your home and family: more powerful boilers cost more
  • The type of boiler you choose: brand as well as whether it’s a combi or conventional (standard) or system boiler
  • The hot water flow rate on a combi: how quickly it heats and supplies hot water
  • The warranty: longer warranty typically costs more
  • Whether you have solar water heating:  works best with a conventional or system boiler to store the water in a tank

Boiler installation costs

Which? investigation found that boiler installation costs could vary by as much as £3,200! Costs of boiler fitting differ, depending on:

  • The amount of work required – are you reconfiguring your heating system? The installation cost for replacing one combi with another is inevitably going to be less than replacing a conventional boiler with a combi, for example. Or does the installation require other services? For instance, scaffolding to get on the roof if that’s where your flue is located (this is the pipe that releases exhaust gases from the boiler outside)?
  • The type of installer – always look for a Gas Safe Engineer to install your boiler replacement.
  • Your location – this might be due to the availability of installers or regional variations in installation costs.

Sometimes the boiler installation cost is included in your quote – as you get through our partner, BOXT.  

engineer responding to an emergency boiler repair

Other boiler replacement costs to consider

If you’re spending hundreds of pounds on a new boiler, you want to make sure that it’s going to work the best it can! So there might be some extra boiler replacement services you want to consider:

  • An extended warranty – Many top-brand boilers come with 10-year warranties. But if yours doesn’t, consider paying extra to extend the warranty beyond its usual period. 
  • New equipment – Consider investing in smart controls or thermostatic valves to control your heating in the most efficient way possible and avoid heating empty rooms. You may also need new radiators if they’re old or don’t work with your new boiler.
  • A system cleanse – Also known as a power flush (or MagnaCleanse system flush from our partner, BOXT). It clears the rust and debris from the heating system, pipes and radiators. Our partner - BOXT – include it as standard as part of their installation.
  • magnetic boiler filter – This clever tool attaches to your central heating system and uses its magnetic powers to attract metallic particles so they don't clog up the pipes. 

Can I get help with my boiler replacement cost?

1. Is it still under warranty?

Some boilers come with warranties of 10 years – and the manufacturer will replace your boiler if it fails in that time. As always, check the small print of every policy – some charge a call-out fee. Others will bill you for installation. And always make sure you register the warranty as soon as your boiler is up and running (most have to be registered within 30 days).

2. Do you have boiler insurance (also known as boiler cover)?

If you’ve taken out an insurance policy to protect your home against boiler breakdown, you might be able to get some help with the cost of a replacement boiler. 

3. What about your home insurance?

Some home insurance plans come with extra services, like home emergency cover. These typically cover things like repairs to your boiler if it breaks down in winter. And they may include a payout should you need a replacement boiler. But it definitely pays to read the small print on all your policies, as some specifically exclude boiler replacement. All will have certain conditions you need to meet too – like servicing your boiler every year (and keeping proof of this).

4. Pay monthly for a new boiler

If you can’t afford the upfront boiler replacement cost, some providers will let you pay for it in monthly instalments instead. Essentially this is a type of loan – much like how you pay for your mobile phone. With a pay monthly deal, you spread the cost of the boiler over a fixed number of months. Bear in mind though there’ll be some interest you pay back each month too, so your total cost is likely to come in higher than the original boiler fee. Take a look at BOXT's finance options

5. Rent a replacement boiler instead

You can rent your home and car… so why not your boiler too? The advantage of this is that you have a fixed monthly cost. There might not be any interest – but you’ll need to put down a deposit. And if you’ve ever struggled to pass a credit check, that might not be a problem when you rent your boiler. But as with any rental agreement, make sure you check any small print for the full details.

6. Look out for special offers

Admittedly, this isn’t a way to lower your boiler replacement cost. But given the high upfront cost for a new boiler, it’s worth checking if there are any deals or special offers available. 

7. Should you buy a second hand boiler?

Occasionally you might find a second hand boiler listed on Gumtree or eBay. But it’s not always a good idea to buy it, especially if you don’t know the boiler’s history. Most people don’t replace their boiler unless it's broken or not working very well. Then there’s the cost of installing it – and paying for future servicing and maintenance. So be very wary of buying second hand. One alternative to consider is a trade-in deal. Some boiler installers will give you a discount on your new boiler as payment for your old boiler. So ask if this is an option when you’re shopping around.

How to get the best boiler replacement deal

We’ve teamed up with BOXT who have been rated number one on Trustpilot for gas boiler installations and heating service so we can help you get a brand new boiler for the best price possible. Through them we offer a fixed price – which includes parts, labour and warranty. And if you need a boiler pronto, they can do next-day installation.

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How to choose a replacement boiler

Work through our checklist to make sure you find the best boiler for you:

1. What size boiler do you need? By all means, pay out more for a better quality brand, but don’t super-size a boiler for the sake of it. Too big and you’ll end up paying for energy you don’t need. Too small, and you might end up with a cold shower after the kids have been in the bath. Get more advice in this size guide from our partner, BOXT.

2. What type of boiler works for your home? From combi boilers to conventional boilers, system boilers to back boilers… there is a range of boiler types out there

3. What fuel type do you use? If you’re replacing a gas boiler, the obvious choice is to go for another gas boiler. But it's worth considering switching to modern-day electric storage heaters or low carbon air source heat pumps. The government has said new homes won't be connected to the gas grid from 2025 so electric vs. gas heating topic is a big consideration.

What happens during a boiler replacement?

Your experience will depend on who’s installing your boiler. But typically the installation will follow these steps:

  1. The installer will turn up and remove your old boiler
  2. Your new boiler will be fitted – along with any new pipework
  3. They’ll test your new boiler and complete any paperwork for you
  4. You’ll be shown how to use the boiler, along with any new smart controls

We’ve teamed up with BOXT to offer a fixed-price boiler – including installation. Find out what makes their installations so special.

boiler engineers installing a new boiler

How long does it take to install a new boiler?

How long’s a piece of string! As with any installation job, it depends on what you’re having done. So if you’re having a straightforward combi replacement boiler, it should only take a day. But if it’s a more complex installation – perhaps you’re replacing a conventional boiler and upgrading your radiators. Or you’re moving the boiler into a new room. It could take two or more days.

Whoever’s carrying out the installation should give you an idea of timescales, what time you can expect them to arrive and the scale of work involved. If in doubt, always ask!

Ready to replace your boiler?

Choose the right replacement boiler for you today with our partner BOXT. Get a fixed price and next-day installation.

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