Why you should plan for your boiler's replacement at every stage of its life

Whether your heating system is newly installed or approaching the end of its life, planning ahead now can help you to avoid costly call-outs in the depths of winter or being forced into a snap decision on an urgent boiler replacement when the time comes. 

Forward planning can open up a wider range of options and ensure you’ve got the right funding in place, especially if you’re interested in low-carbon heating options. It also gives you the opportunity to make other improvements to your home that will help pave the way to a lower-carbon, more cost-effective future.

Wherever you are in your boiler’s lifespan, our free personalised energy planning service will show you where you can make improvements to your home’s energy efficiency and how much it will cost. Try it out and start your home’s tailored energy plan: use our home energy planning tool.

Why you should avoid a last-minute boiler decision

A third of boiler owners in our last survey* said their boiler broke down unexpectedly and needed to be replaced. If this happens when it’s freezing cold, you'll need a replacement as soon as possible, leaving you with little time to make a well-informed decision and consider all your options. 

In the same survey, 14% told us they'd consider swapping to an air source heat pump for their next heating system, 10% would consider a ground source heat pump, 7% a biomass boiler and 16% a hybrid heat pump and boiler system.

Combining an efficient heat pump with an energy tariff that discounts the energy used to run it can make heat pumps a temptingly cost-effective choice, as our research has found.

Read more: use our calculator tool to help maximise your heat pump savings with a specialist tariff in our guide to air source heat pump costs and savings

However, installing low-carbon technology isn’t an overnight decision you can make when your boiler has already broken down. With longer lead times and the option to make other improvements to your home’s setup – perhaps with some additional insulation, for example – it’s worth planning well in advance. 

Even if you just want a like-for-like replacement for your boiler, keeping it well maintained and having a plan in place means you'll know how you're going to pay for it and who will carry out the work.

Here are our top tips, depending on your boiler's current condition:

1) If your boiler is new or in good working condition

It’s a good idea to check the small print of your boiler’s warranty, which often requires an annual boiler service to remain valid. 

Even boilers that are working well may not be operating at optimum efficiency. During a boiler service, your engineer can set yours up to make instant energy savings by making the most of its settings and features. 

Summer is a good time to book a service, as heating engineers are less busy. Get our top tips for making the most of your appointment, and find out how much you can expect to pay, in our guide to getting the best boiler service.

No matter what heating system you have, you’ll save money on your bills by keeping the heat you generate inside your home. If your boiler is still new and you’re not worried about needing a replacement any time soon, it’s a good time to put your savings towards other home improvements that will lower your bills by making your home more energy efficient. You’ll start to see a return straight away, and you’ll also be futureproofing your home so that it’s optimised for a low-carbon heating system in the future.

Insulation

• Loft insulation is one of the best - and most affordable - places to start improving your home’s energy efficiency.
• Our guide on how to buy loft insulation takes you through the options and costs. It also explains what you can do yourself with a little know-how, and when you'll need to ask an expert. 
• Insulating walls and floors are bigger, more disruptive jobs, but can have big rewards. If you’re having other building work done, it’s worth factoring in insulation at this stage to minimise disruption and make your home improvements more cost-effective. See our guide on how to insulate your home for more information. 

Double glazing

• It's an expensive job, but updating your windows will give instant rewards, making your home cosier in winter and keeping it cooler in summer. It will warm up quickly and for longer when your heating is on, making your home cheaper to heat. You'll also benefit from better sound insulation.
• Get started with our guide on how to buy double glazing.

2) If your boiler is starting to develop minor faults

As your boiler starts to age, it’s even more important to keep up regular servicing and maintenance to keep it going for as long as possible. Because heating systems are so expensive to install, it’s rarely cost-effective to replace a boiler ahead of its time. You’re better off making sure you have some savings ringfenced for repairs as and when you need them. 

Our research consistently finds that, on the whole, you’re better off paying ad hoc for boiler repairs, rather than taking out insurance policies that can have spiralling premiums. However, in some cases – if your boiler is particularly unreliable, for example – you might prefer the peace of mind that comes with a policy. You might also get it as part of a packaged deal, for example with home or contents insurance, so see whether you're entitled to anything through other policies you have, to make sure you’re not paying twice.

Our guide on how to choose the best boiler cover explains whether you need it and how much it costs. 

Finding a boiler engineer you can rely on, who knows your home and your system already, can be an invaluable resource as your boiler ages. 

Which? Trusted Traders vets local traders and ensures they have all the right certifications and credentials. Check past customer reviews and find a heating engineer near you at Which? Trusted Traders.

Or, see our ranking of bigger, national boiler-servicing firms, along with tips on what to ask about, in our guide to getting the best boiler service.

Planning ahead for your next heating system

At this stage in your boiler’s life, it’s really worth making a plan for what might come next. 

If you’re likely to want another boiler, bear in mind that this will be a big expense. While financing options are available, it’s always best to pay upfront if you can, so start ringfencing some savings so you won't be caught off guard by a big bill later on.

Our guide to how much a new boiler costs talks you through the options. Or read our guide to the different types of savings account.

If you’re interested in switching to a low-carbon heating system such as a heat pump or a hybrid system, this stage in your boiler’s life is a good time to start researching what's available and the routes to financing. 

Many UK homes are heated by 'wet' central heating – this uses a fossil-fuel-powered boiler to heat water, which is then circulated through pipes. But there are lots of other models out there, all of which have different pros and cons for different types of home. You can also put together hybrid systems that use a variety of technologies for different things, in different parts of your home, or at different times of year. 

Read more about: the different types of home heating system.

Talking to an expert about what could work for your home in the future can be invaluable. If you have a forward plan in mind for building work you might need and what you might expect to spend, you can do the work gradually as and when it suits you. Plus, you can keep an eye out for any relevant grants or discounts that might help with costs.

Upgrading your central heating

• Air-to-water heat pumps are the most common type installed in UK homes. They operate by passing water through your central heating system, so can be most closely compared to a typical boiler system. However, they tend to heat water to lower flow temperatures than boilers. This means heat pumps can be more efficient to run if you have large heat emitters (ie radiators) throughout your home.
• You can get an assessment at any time to see whether your home’s radiators are up to the task. If they need to be upgraded, you might choose to do this ahead of time to spread out the costs.   
• Wet underfloor heating is, in essence, simply turning your floor into a very large radiator that runs at a low flow temperature, so it can pair very well with a heat pump system. It’s expensive to install, but if you're doing other renovation work, you could consider combining the two. 
• Read more in our guide to wet underfloor heating, including how it works, installation and running costs, plus testimonials from homeowners who've had it fitted.

3) If your boiler is nearing the end of its life

By the time your boiler is showing signs that it might not last much longer, or if it’s particularly old, a plan is essential. 

Find out more: 5 signs you might need a new boiler

Research your options, and make sure you have a heating engineer you trust on hand.

If your next system is going to be a boiler, see our guide on how to buy the best boiler, think about your boiler costs and see our ranking of the best boiler brands. 

We don’t recommend replacing a functioning boiler before its time. But if yours is unlikely to last the winter, having a plan ready will spare you the chaos of a last-minute decision.

Replacing a boiler with a heat pump

If you’re interested in switching to a heat pump, you’ll need to get prepared earlier: while a like-for-like boiler replacement often takes only a few days, a heat pump is likely to take a few weeks.

Look for local heat pump installers who come well recommended, and ask for a selection of quotes. Some energy companies and banks offer deals on heat pumps and installation. To access the government’s Boiler Upgrade Scheme (BUS) grant, you’ll need to use an MCS-registered engineer. The grant offers a discount of £7,500 on the upfront price for homeowners in England and Wales. The Scottish government also offers a similar scheme.

Read more on: air source heat pump costs and savings, which includes our heat pump running costs and savings calculator. Plus, find out how to access the government’s Boiler Upgrade Scheme.

Generally, you'll need space outside for an external condenser unit (roughly 1 x 1 x 2m), plus a one-metre clearance for airflow. Inside, the heat exchanger takes up about the same space as a gas boiler. The closer you can place this to the outside unit, the better. Integrated systems are available, which combine the heat exchanger and hot water cylinder into one unit, which is roughly the size of a fridge freezer. Otherwise, you'll need a separate hot water cylinder too.

It’s possible to install heat pumps in flats and terraced houses with less space, although this might come with additional challenges. A good installer should be able to explain your options and what, if any, work your home might need to get set up. For small flats, particularly those that already have electric heating and hot water, an air-to-air heat pump might be a good choice, although these aren’t currently covered by the BUS grant. 

See testimonials from Which? members who have had heat pumps installed in a variety of different homes, and their opinions (both positive and negative), in our guide: what it’s really like to have a heat pump.

Head to Which? Trusted Traders to find vetted local heat pump engineers near you. You can also use the MCS Register to find certified installers of heat pumps, solar panels and other green tech in your area.

Use our personalised home energy planning service

If you're interested in making your home more energy efficient, it can be hard to know where your money is best spent and what types of installation would benefit your home's specific needs. That’s where our home energy planning tool can help. It cuts through the confusion, giving you information tailored to your property. Using data you input, as well as your EPC reports and other specifics, the tool will tell you how you can reduce your energy bills and how much it might cost upfront. 

You can get started with a plan and make any initial updates when your boiler is still working, ensuring you're well set up and ready to act when you do need a replacement.

Find out more and try our home energy planning tool to start your personalised plan.

*Our research: May 2024 UK general public online survey of 10,028 people who are responsible for the maintenance of their boiler, and our May-June survey of boiler engineers.