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Upgrading your boiler

Upgrading your boiler

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Last updated: 28 June 2022

With energy costs on the rise, households across the country are looking for ways to reduce their bills. But did you know that heating and hot water typically accounts for more than half of your home’s energy usage? 

Knowing this and making relevant upgrades to your boiler can go a long way to reducing your energy bills, as well as lowering your carbon footprint - something we can all get on board with.

If you’ve been using the same boiler for a good few years, it’s probably time for an upgrade. Modern boilers are much more efficient than older models, and the savings you can make by upgrading to a newer machine (up to £580 per year) can go a long way to ease the surging cost of living. 

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Do I need a new boiler?

Generally, the newer your boiler is, the more efficient it is at using energy. In other words, they use less gas or electricity to heat water up, which of course means they cost less to do their job. So, if your current boiler is 10 years old or more, then you can likely make significant savings by upgrading to a more modern and more efficient heating system.

It’s important to note that while investing in a new boiler will come with a significant upfront cost (upgrading your boiler can typically cost more than £4,000), this shouldn’t put you off as thanks to its much-improved efficiency, you should make this investment back in a few years through lower energy bills. This is even more true today with soaring wholesale energy costs.

How much can I save with a new boiler?

According to research from the Energy Saving Trust, replacing an old gas boiler costs around £4,000 on average, while it would typically cost you around £4,700 to replace an oil boiler.

However, upgrading your boiler should be seen as a long-term investment, with the money saved in lower energy bills paying back the initial cost of the new boiler over a number of years.

All boilers have an energy-efficiency rating, with A being the most efficient, and G being the lowest. Therefore, the amount you can save on your energy bills with a new boiler will depend on what type of boiler you’re replacing, as well as the type of home you live in.

According to EST, this is how much you could save on average if upgrading to an A-rated boiler:

Type of home: Annual savings (upgrading from a D-rated boiler): Annual savings (upgrading from an E-rated boiler): Annual savings (upgrading from an F-rated boiler): Annual savings (upgrading from a G-rated boiler):
Flat £80 £90 £105 £150
Bungalow £170 £185 £210 £300
Mid-terrace house £180 £200 £225 £325
Semi-detached house £215 £235 £265 £380
Detached house £260 £315 £405 £580

What to consider when upgrading your boiler

It’s important to know what to look for when upgrading to a more efficient boiler. There’s a lot of choice out there, and while generally the newer models will be the most efficient, you should also be aware of the different types of boiler available.

You should also be aware of the fact that from 2025, traditional gas and oil boilers will be banned from all new homes in the UK. This is due to the government’s commitment to becoming carbon neutral by 2050. This means you should also be considering alternative, future-proof heating systems, such as ground-source heat pumps.

Another alternative would be to get a hydrogen-ready boiler. These are gas boilers that have the ability to burn either gas or pure hydrogen. As burning hydrogen doesn’t produce any carbon dioxide, it has a much lower carbon footprint. Many of the latest energy-efficient boilers are hydrogen-ready, meaning they can easily be switched over to hydrogen sources once the grid is ready.

The types of boiler you should consider to improve your home’s energy-efficiency include:

Condensing boilers

Most modern gas boilers are ‘condensing’ boilers, and they’re also the most efficient. Since 2005, almost every new gas boiler that has been fitted in UK homes should have been a condensing boiler, including both system and combi boilers.

Condensing boilers are more efficient than non-condensing ones as they recover some of the lost heat from its exhaust flue, using it to further heat the central heating water. This means that less heat, and thus less energy, is lost overall.

How do I know if my current boiler is a condensing boiler?

It’s pretty simple to work out if your boiler is a condensing boiler or not, by either looking at it or finding records (if you can’t remember!) of when it was installed:

  • If the boiler’s flue, which looks like an exhaust pipe, is made out of plastic, then it is most likely a condensing boiler. If it’s made out of metal, however, then it’s probably time for an upgrade.
  • Condensing boilers also have a plastic pipe that extends from the bottom of the boiler, through a wall and into a drain.
  • If you’re still not sure, try to look for any records for when it was installed. If it’s a gas or LPG boiler, it will be condensing if it was installed after 2005. And if it’s an oil boiler, then any one installed after 2007 will be condensing too.

System boilers

All condensing gas boilers are either ‘system’ boilers, or ‘combi’ boilers, with system boilers edging it in terms of efficiency.

System boilers include a water cylinder which is used to store any heated water for future use. However, while this means its more efficient than combi boilers in producing hot water in the first place, heat is inevitably lost from the stored water over time, meaning they lose efficiency in the long run.

Combi boilers

Combi boilers, unlike system boilers, don’t have a water cylinder or anywhere else to store hot water. Instead, they heat water on demand.

This means that more energy is required to initially heat your water or home than a system boiler, but they are much less wasteful in the long run in terms of energy lost.

Which type of boiler is right for me?

So, we’ve established that system boilers are more efficient in the short term, but combi boilers tend to be more efficient over long periods of time. This can make it confusing knowing which one to go for.

However, this decision should be made easier by the type of household you live in and how much energy and hot water you use.

A system boiler may be better for you if:

  • You have a large family or generally use a lot of hot water.
  • You have a large home with enough space for a chunky boiler - system boilers are bigger than combi boilers.
  • You have home solar panels or are thinking of investing in some in the future.
  • You have a heat pump or are thinking of getting one later on.

However, a combi boiler may more be beneficial if:

  • You live alone or just with one other person.
  • You are away from the property for long periods or you generally don’t use much hot water or central heating.
  • You have a small home with no space for a large system boiler.

Is there anything else I can do to make my boiler more efficient?

Yes. You don’t necessarily have to fork out thousands of pounds for a new boiler to improve your home’s heating system’s efficiency.

Here are a few things you could do with your current boiler to improve its efficiency:

  • Install a heating control system, such as a smart thermostat, and hook this up to your boiler. This allows you to have more control over your water heating system, make changes accordingly and save money on your bills.
  • Install a flue gas heat recovery system. This is designed to trap any lost heat and recycle it in the boiler, further heating your water without having to use any more energy. However, this would only work on much older boiler models, as the newer condensing boilers already use this technology.
  • Get a new hot water cylinder. These hot water storage units are designed to be well insulated so as to lose minimal heat. However, their efficiency will degrade over time, so it might be worth either topping up the insulation, or investing in an entirely new cylinder altogether.
  • Use chemical inhibitors, which help to slow down the corrosion on the inside of your boiler, as well as helping to prevent the build-up of limescale and sludge, all of which contribute to the efficiency of your heating system.
  • Fit a magnetic filter in the bottom of your boiler. This will attract any rust, thus helping to remove it from the heating water and improving the overall efficiency.

How to find an installer

Finding an installer to come and fit your new boiler is made easier with usave and our partners Boiler Central. We compare quotes from a range of different boiler fitters in your area, and all of the installers we compare are Gas Safe registered.

Simply enter your postcode and provide a few details about your home, your energy usage, and which type of boiler you want to upgrade to, and we’ll provide you with a list of quotes from a range of boiler brands in seconds.

You can then choose your installation date and payment method, with next-day fittings available in most cases. You also have the option to pay in monthly installments, or even to defer your payment until 2023, and no deposit is required whatever method you choose.

You can save up to £580 per year by upgrading your old boiler today, but for even better savings, use the promo code MAY to get £50 off your new boiler installation.


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Fergus Cole

Author: Fergus Cole

Fergus is a journalist specialising in the personal finance, energy and broadband sectors. He also has a passion for travel and adventure so tries to make the most of this in any spare time he gets.

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