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Last updated: 3 November 2023

12kW Boilers – Everything You Need to Know

12kw boiler

If you’re looking for a new boiler and live in a flat or smaller home, then you’ve come to the right place! A 12kW (kilowatt) boiler is likely a good choice for your home’s heating and hot water needs. In this article, we’ll talk you through some of the different types of boilers available in 12kW.

First things first, how do you know if 12kW is actually the right size for your home? Generally speaking, checking how many radiators you have is a good indicator of what size of boiler you’ll need. We’ve put together a guideline below:

No. of RadiatorsCombiSystemHeat-only
Up to 1024-27kW9-18kW9-18kW
Up to 1528-34kW18-26kW18-26kW
Up to 20 (and over)35-42kW27-40kW27-40kW

As you can see from the table above, you not only need to think about your boiler’s output size (kW) but also whether you want a combi, system, or heat-only boiler. Depending on the boiler type, you can generally expect the cost of a 12kW boiler to range anywhere from £695 to £2,425.

And that’s not all – you’ll also need to consider factors such as the efficiency rating and warranty length of your boiler to know whether you’re getting good value for money or not. This is why it’s important to do your research and compare different boilers in order to find one that’s a perfect fit for your home.

As well as comparing boilers, you should also compare the rates of different installers. For example, a local installer may offer you a better deal than a larger company as they don’t have to spend as much on travel costs. However, finding qualified and reliable installers can be a challenge if you don’t know what to look for, and you can end up wasting hours of your time and feeling frustrated.

Let GreenMatch help you. We have a wide network of vetted UK boiler installers who we can quickly connect you with. You’ll receive up to 3 quotes from each heating engineer, which you can then easily compare to select the best deal. All you have to do is click the button below to receive your free, non-binding quotes now.

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12kW Electric Boilers

A 12kW electric boiler is perfect for a flat or smaller home. It should not only be able to meet your heating and hot water needs, but electric boilers also tend to be more compact compared to the average gas or oil boiler, making it ideal for saving space.

Electric boilers can also be a great option if you’re looking to reduce your carbon footprint. This is because, unlike gas and oil boilers, electric boilers do not release emissions whilst operating.

However, one caveat to this is that you need to consider where your electricity is coming from if you truly want to reduce your carbon emissions. Unfortunately, most electricity in the UK is currently generated from burning fossil fuels. However, potential alternatives to combat this are available, such as opting for a green energy supplier to increase the amount of green electricity in the grid or by installing your own photovoltaic panels.

Here are some top electric boiler options, all with 99.5% – 100% efficiency ratings, for you to consider:

  1. Electric Heating Company – SlimJim 12kW Electric Flow Boiler
  2. Ferroli – LEB 12.0 TS 12kW Electric Boiler
  3. Heatrae Sadia – Amptec 12kW Electric Boiler

If you’re curious about getting an electric boiler for your home but aren’t sure where to start, then we recommend contacting a qualified installer who can help answer any questions you may have.

By clicking the button below, we can put you in touch with up to 3 qualified boiler installers in your area. This way you can get top advice and also compare their quotes to ensure you’re getting the best deal. And what makes this even better is that it’s completely free and you’re not obliged to accept any of the offers you receive.

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12kW Combi Boilers

Combi boilers are the most popular type of boiler in the UK. This is mainly for two reasons. Firstly, it’s compact and doesn’t require any extra components, meaning it can easily fit in one of your kitchen cupboards. Secondly, it can provide hot water on demand so you don’t have to wait for it to heat up.

A 12kW combi boiler is generally recommended for flats and smaller homes with less than 10 radiators.

Oil and gas combi boilers with 12kW are not very common, so our following list with the best combi boiler in the UK for this size consists of 12kW electric combi boilers.

1. Electric Heating Company Fusion Comet Electric Combi Boiler 12kW

Electric Heating Company Fusion Comet Electric Combi Boiler 12kW

The great thing not only about this particular model but electric boilers in general is that you won’t have to worry about carbon monoxide leaks or emissions being produced while your boiler is operating (however, with that being said, you still need to consider how your electricity is being generated and the emissions released during that process).

This 12kW electric combi boiler is considered to be a good fit for homes with 8 radiators. However, if you have less radiators in your home then the 6kW or 9kW models might be a better fit for you. Equally, if you have 10 radiators then your home then you should consider the 14.4kW model.

Some great features of this boiler include an energy-saving smart pump and also a solar DHW (domestic hot water) connection. These both give the potential to reduce your carbon footprint as well as your energy bills.

    • Efficiency: 100%
    • Liquefied Petroleum Gas (LPG) Compatible: No
    • Central Heating Output: 12kW
    • Warranty: 2 years
    • Estimated price (excl. installation): £2,425

2. Electric Heating Company Fusion Astro 12 kW Combi Electric Boiler

electric heating company fusion astro 12 kw combi electric boiler

Another top boiler from the Electric Heating Company is the Fusion Astro. Alongside the 12kW model, it is also available in output sizes 14.4kW, 18kW, and 24kW, so you’re likely to find something that suits your needs.

The Fusion Astro is a combi boiler, however, if for example you own a bath and need a bit more hot water, then it can be redesigned to heat water in a cylinder. Some other great features of this boiler include quiet operation, quick heat-up times, and is compatible with underfloor heating.

    • Efficiency: 100%
    • Liquefied Petroleum Gas (LPG) Compatible: No
    • Central Heating Output: 12kW
    • Warranty: 2 years
    • Estimated price (excl. installation): £1,300

3. Elnur Mattira MAC15 12kW Electric Combi Boiler

Elnur Mattira MAC15 12kW Electric Combi Boiler

The last 12kW combi boiler on this list is Elnur’s Mattira MAC15. It can be wall mounted and has selectable outputs from 3kW up to 15kW, meaning you can have full control over your boiler’s output and save energy.

It includes a digital display with user-adjustable controls as well as allows for adjustable temperature regulation. Furthermore, it is also suitable for homes with underfloor heating.

    • Efficiency: 100%
    • Liquefied Petroleum Gas (LPG) Compatible: No
    • Central Heating Output: 12kW
    • Warranty: 2 years, 5 years for cylinder
    • Estimated price (excl. installation): £2,400

Finding a new boiler as well as a reliable installer at a fair price can be a daunting and tedious task… But what if we told you that it doesn’t have to be this way? GreenMatch can make the process of finding a qualified boiler installer easy for you.

Since GreenMatch has a vast network of qualified heating engineers, we can quickly connect you with up to 3 reliable boiler installers near you. You’ll receive a free quote from each installer, so you can easily compare them and choose the best deal. This way you’ll save time and avoid being overcharged. Click the button below to get your free, non-binding quotes now.

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12kW System Boilers

A system boiler is essentially a type of boiler that works in conjunction with a separate water cylinder in order to provide heating and hot water to your home.

System boilers come in a range of sizes including 12kW. Generally, system boilers are a good match for larger homes, however, in this case if you have a smaller home with no more than 10 radiators then a 12kW system boiler should be a good fit.

Below you’ll find a list of some of the best system boiler 12kW options available to give you an idea of what choices you have for your home:

1. Baxi Assure System 12kW Gas Boiler

Baxi Assure System 12kW Gas Boiler

Baxi is one of the leading boiler manufacturers in the UK. The Assure System is one of the boilers it offers in 12kW. And if you’re still not sure whether you might need a bit of extra power or not, this particular model is also available in 15kW, 18kW, and 24kW.

This boiler is compatible with Baxi’s uSense smart thermostat, meaning you can control your home’s heating system wherever you are. You no longer need to worry about turning it off before leaving the house! Furthermore, Baxi states that it is a fully modulating boiler that uses exactly the right amount of fuel, so you can feel assured that most of the energy is going towards heating your home.

    • Efficiency: 93%
    • Liquefied Petroleum Gas (LPG) Compatible: No
    • Central Heating Output: 12.9kw
    • Warranty: 2 years
    • Estimated price (excl. installation): £900

2. Vaillant ecoFIT pure 612 (12kW) System Gas Boiler

vaillant ecofit pure 612 12kw system gas boiler

Vaillant has been in operation for over 100 years and has received the German Quality Award for the high standard of its products. The ecoFIT pure system boiler is no exception to this standard. As well as the 12kW model, it is also available in 15kW, 18kW, 25kW, and 30kW.

One of the standout features of this boiler is that it has a high specification aluminium heat exchanger; this is included to help make the boiler easier to maintain so that it can last longer and help reduce your energy bills. Furthermore, it also has a clear LED display, helping to give visibility so you can see what you’re doing even if your boiler is located somewhere with little light.

    • Efficiency: 94%
    • Liquefied Petroleum Gas (LPG) Compatible: No
    • Central Heating Output: 12.3kW
    • Warranty: 10 years
    • Estimated price (excl. installation): £894

3. Worcester Bosch Greenstar 4000 12kW System Gas Boiler

Worcester Bosch Greenstar 4000 12kW System Gas Boiler

Worcester Bosch is one of the highest-rated boiler brands in the UK and its Greenstar range has won the Which? Best Buy award. The 12kW boiler is the smallest size available in this model. However, it’s also possible to have it in size 15kW, 18kW, 21kW, or 24kW if you think you might need a little more power.

According to Worcester Bosch, this is its quietest system boiler so you don’t have to worry about it disturbing the peacefulness of your home. Another great benefit of this boiler is that it can be used with Bosch’s Greenskies solar panels, meaning you can do your bit for the environment and also not have to rely as much on the gas grid.

    • Efficiency: 97%
    • Liquefied Petroleum Gas (LPG) Compatible: LPG model available
    • Central Heating Output: 12kW
    • Warranty: Up to 10 years
    • Estimated price (excl. installation): £975

As you can already see, there are a lot of viable options to choose from. It can be difficult to figure out which model would be the best for your home. That’s why we recommend talking to a qualified heating engineer. This way you don’t have to stress about whether you’re making the right decision or not, and can feel confident that your heating and hot water needs will be met

However, instead of just talking to one heating engineer, it’s a good idea to talk to multiple so you can make sure that you’re getting unbiased advice and are also able to compare their quotes to ensure that you’re getting the best deal. By clicking the button below, we can provide you with up to 3 free quotes from qualified heating engineers in your area. It takes less than a minute, and you’re under no obligation to accept any of the quotes you receive.

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12kW Heat-Only Boilers

A heat-only boiler, also referred to as a regular or conventional boiler, is the most traditional type of boiler heating system in the UK. What distinguishes a heat-only boiler from other types of boilers is that it requires extra components to function: a water tank in your loft and a hot water cylinder in an airing cupboard.

Something important to note is that heating engineers typically do not recommend installing a heat-only boiler. This is because the installation process is relatively more complex and expensive compared to other boiler types.

However, with that being said, if you already have a heat-only boiler installed in your home and simply want to replace it with a newer model then this may still be a great option for you.

Heat-only boilers with 12kW output size are suitable for homes with up to 10 radiators. Below you can see some of the best boiler manufacturers with heat-only boilers in this size:

1. Ideal Logic Max Heat H12 Heat-Only Gas Boiler

ideal logic max heat h12 heat-only gas boiler

Ideal is a British boiler manufacturer which has been around for over a century. This particular 12kW boiler is part of its renowned flagship range, and also comes in output sizes of 15kW, 18kW, 24kW, and 30kW.

First of all, this boiler has been designed with the idea of making installation and servicing easier with its low weight and accessibility. This means you’ll be able to save both time and money. Furthermore, it is hard wearing and scratch resistant so you don’t have to fret too much about it being damaged.

    • Efficiency: 93%
    • Liquefied Petroleum Gas (LPG) Compatible: No
    • Central Heating Output: 12kW
    • Warranty: 10 years
    • Estimated price (excl. installation): £885

2. Baxi 412 Heat 12kW Heat-Only Gas Boiler

baxi 412 heat 12kw heat-only gas boiler

Another boiler from Baxi is the 412 Heat. If you’re not sure whether the 12kW model will be powerful enough for your home’s needs, then you can also choose between 15kW, 18kW, 24kW, and 30kW boilers.

This boiler comes with flexible flue options, making it suitable to install in a variety of locations in your home. It is also known for its quiet operation so you don’t have to worry about any disturbances, as well as its low weight of 19.5kg which makes installation easier.

    • Efficiency: 93%
    • Liquefied Petroleum Gas (LPG) compatible: No
    • Central Heating Output: 12kW
    • Warranty: 5 years
    • Estimated price (excl. installation): £695

3. Worcester Bosch Greenstar 12Ri Regular Gas Boiler

Worcester bosch greenstar 12ri regular gas boiler

Another popular boiler from Worcester Bosch’s Greenstar range is the 12Ri. This 12kW model has the lowest output in the range, but if you’re unsure about whether that’s powerful enough for your home, then 15kW, 18kW, 21kW, 24kW, 27kW, and 30kW are also available for you to choose from.

Like the previously mentioned Greenstar boiler, this model is also compatible with Bosch’s Greenskies solar panels, helping you save energy and money. Furthermore, it also includes frost protection, giving you peace of mind that your boiler will operate at optimum levels all year round.

    • Efficiency: 92%
    • Liquefied Petroleum Gas (LPG) compatible: Yes
    • Central Heating Output: 12kW
    • Warranty: Up to 8 years
    • Estimated price (excl. installation): £814

It’s important to keep in mind that the prices included in this article for each 12kW boiler are only an estimate. And in addition to that, you’ll also need to consider the installation costs. The total cost of a new boiler can vary a lot depending on the type of boiler you get, your location, and the installer’s rates.

This is why it’s a good idea to get quotes from multiple boiler installers so that you can compare prices and avoid being overcharged. Simply click on the button below and we’ll send you up to 3 quotes from qualified installers so you can objectively choose the best deal. On top of this, our service is completely free and you’re under absolutely no obligation to accept any of the offers.

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FAQ

Bronte McClelland
Written by Bronte McClelland, Writer

Brontë is an experienced writer and editor for GreenMatch. Her passion for sustainability and renewable energy drives her to stay at the forefront of green-energy trends.

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