Best System Boilers in 2024: Prices and Comparison

System boilers are a great option to consider, especially if you have a medium or the best system boiler for a large house or if your household has a high hot water demand. Below we’ve listed some of the best system boilers currently available on the UK market, so that you can get a better idea of what type of boiler is best for your home based on factors such as output size, price, and efficiency.

If you don’t want to spend hours scrolling through the internet trying to figure out which boiler is the best value for money or which installers are available and legitimate, then we recommend comparing boiler quotes through GreenMatch. This way you’ll save time and effort, and also be able to choose the best deal.

Simply click the button below to receive up to 3 quotes from qualified installers in your area. This is completely free of charge and you’re under no obligation to accept any of the quotes.

System boilers are a popular heating system option for many homes in the UK. This is further reflected by the fact that the top boiler manufacturers create a variety of system boiler models for the UK market. You’re spoilt for choice!

However, as we all know, having too many options can be both a blessing and a curse. It means manufacturers are competing against each other to create the best quality product, however, researching system boilers can also be a long and tedious process.

So how do we know which system boiler is the best to choose in 2024?

At GreenMatch, we’ve put together a list of 5 of the best condensing system boilers on the UK market to save you time and effort on researching boilers individually. We’ve based this list on top-quality brands, as well as the specific boiler’s efficiency and reliability.

Viessmann has a long history as a renowned boiler manufacturer dating back to 1917. Their popular Vitodens 100-W model is available as a system boiler, as well as combi and conventional.

This system boiler is available in output sizes of 11kW, 19kW, 25kW and 32kW, so it is likely to be suitable for your home whatever your hot water demand may be.

Furthermore, this boiler is highly efficient, as it is A-rated with a 94% efficiency rating. This means only 6% of the energy you use is wasted, which in turn means you are also wasting less money.

Viessmann also provides a standard warranty of 5 years which can be extended to 12 years if installed by a Viessmann Academy Trained Installer. This warranty period should assure you of Viessmann’s confidence in the quality and reliability of their products.

As we all know, gas is not the best fuel type for the environment. However, Viessmann along with many of the other top boiler manufacturers are working towards a more sustainable future. This is why the Vitodens 100-W model is ready for when the National Grid makes the switch to a 20% hydrogen blend.

Some other notable features of the Vitodens 100-W System Boiler are:

Vaillant is another top boiler manufacturer. One of the best Vaillant system boilers is the ecoTEC plus; it is even considered to be their flagship boiler.

This model is suitable for a variety of homes as it is available in multiple output sizes including 12kW, 15kW, 18kW, 24kW, 30kW and 37kW.

It is highly efficient with an efficiency rating of 94% and ErP (Energy-related Products) A-rating for heat, meaning it has the potential to reduce your energy bills and carbon footprint.

Vaillant are confident in the quality of their boilers, offering a standard warranty of 5 years that can be extended to 7-10 years if installed by a Vaillant Advance Installer.

As part of the HyDeploy project, Vaillant has been testing their boilers with up to 20% hydrogen blend. This includes the ecoTEC plus model series, which is equipped with an IoniDetect combustion system, enabling it to automatically adapt to fluctuating gas qualities. Vaillant is also currently working towards 100% hydrogen ready boilers to help reduce greenhouse gases.

Some other notable features of the Vaillant ecoTEC plus System Boiler are:

Ideal is a British company which has been producing boilers for over a 100 years. Their Ideal Logic Max boiler is available as a combi or regular boiler, as well as a system boiler.

The central heating maximum output is available in sizes 15kW, 18kW, 24kW and 30kW. So, if you have a smaller home then the 15kW could be a good fit, whereas if you have a larger home with about 15-20 radiators then the 30kW may be the option for you.

Similar to the other top system boilers, the Logix Max is also A-rated and has an efficiency rating of 93%. Financially, this means for every £1 you spend on heating your home with a 93%-efficient boiler, only 7p is wasted.

This boiler model is considered to be reliable, as it comes with a 10 year labour and parts warranty if registered within 30 days of installation and serviced annually.

This model is already capable of running safely and efficiently on a 20% hydrogen blend. Meaning you’ll be prepared for the National Grid’s plans to heat UK homes in a more sustainable manner.

Some other notable features of the Ideal Logic Max System Boiler are:

Worcester Bosch is another well-established boiler manufacturer which has implemented Corporate Social Responsibility (CSR) policies in various areas, including their environmental impact.

This model is only available in two sizes: 30kW and 35kW. This means it is suitable for homes with around 20 radiators – always make sure to check which size your home needs with a qualified heating engineer.

As the Greenstar 8000 Style is one of the best available system boilers on the market, this means it has a superb efficiency rating of 94% and an ErP A-rating for heat.

The standard warranty for this model is 5 years, however, it can be extended to 12 years if you have it installed by an accredited Worcester Bosch installer. Considering the fact boilers should ideally be replaced around the 10-year mark, this means the warranty will cover your boiler’s entire lifespan.

Worcester Bosch’s entire gas boiler range is capable of running on a 20% hydrogen blend. On top of that, their Hydrogen Ready boiler prototype won the award for Best Heating Innovation at the Green Home Awards.

Some other notable features of the Worcester Bosch Greenstar 8000 Style System Boiler are:

Baxi is another British company that was founded way back in 1866. They have won a number of awards over the years including the Net Zero Hero award from the HVR Awards in 2020.

This model comes in two sizes: 18kW and 24kW. That means these sizes are suitable for homes with up to approximately 15 radiators. If you live in a larger home or have a high hot water demand then you should probably consider another model with a larger output size, such as the Vaillant ecoTEC plus.

If you opt for a Baxi 800 then you’ll be receiving an ErP A-rated boiler with a 93% efficiency rating. This means you’re only wasting 7% of the energy you use to heat your home.

Baxi boilers are reliable and it is possible to have the guarantee of a 10 year parts and labour warranty. This means you can have peace of mind that your boiler will be covered throughout its lifespan.

As mentioned, Baxi have won the Net Zero Hero award and are currently working on multiple projects towards a more sustainable future. At present, this model is certified to work with a 20% hydrogen blend.

Some other notable features of the Baxi 800 System Boiler are:

While it’s good to have an idea of which type of boiler you need, it can be difficult to know for sure which type of boiler is best suited for your home without expert knowledge. You may end up unnecessarily stressing yourself out to only waste money on your heating bills. That’s why we recommend talking to professional heating engineers to ensure you have a smooth installation process with no extra costs.

Simply click the button below to get up to 3 comparison quotes from qualified boiler installers in your area. This way you can have peace of mind that you won’t be wasting money on heating bills and you also won’t be overpaying for upfront costs. It’s completely free of charge and you’re under no obligation to accept any of the quotes.

When talking about the size of a system boiler, this is generally referring to the boiler’s output size and how powerful it is, rather than its physical dimensions. The output rating is measured in kilowatts (kW).

It’s important to note that the largest output size isn’t necessarily the best option for your home. If you get a larger output size than you need, you’ll end up wasting energy and money for no reason. Alternatively, if you get a boiler that isn’t powerful enough then your radiators and hot water will struggle to heat up fully.

Generally speaking, for every radiator you have you’ll need 1.5-2kW of power. Below is a rough guide on what output size you’ll need for your home depending on the number of radiators you have:

The above table is only meant as a guide. Other factors, such as your household’s hot water usage and the insulation of your home may affect which output size is most appropriate for your home’s specific needs.

It is also advised to not solely base your new boiler’s output size on the size of your current one. This is because your home’s circumstances may have changed over the years, such as fitting a new bathroom or family members moving in and out. Equally, your current boiler may even be too powerful, meaning you could save on your energy bills with a smaller size.

As already mentioned, system boilers are generally suitable for medium and larger sized homes. Therefore, if you have a 4-bedroom home a system boiler is likely to be a good fit for you.

Four-bedroom homes in the UK typically have up to 15 radiators. Therefore, a system boiler of 18-26 kW is likely to be suitable for your home, such as the Ideal Logic Max.

However, if you have more or less radiators in your home, we recommend you check the table above to get a better idea of which option best reflects your circumstances. Furthermore, we always advise to check with a qualified heating engineer before installing your new boiler and hot water cylinder.

On average, it costs £650-£2,500 to install a system boiler in the UK. However, installation costs can vary widely depending on a multitude of factors such as:

Of course, you will also need to take into consideration the upfront and running costs of your new boiler.

If you have a medium or larger sized home then a system boiler could be a smart choice for you, as it is likely to meet your heating and hot water needs.

On the other hand, considering it’s 2024, there are an abundance of suitable options available to you. Many system boiler manufacturers are preparing for a greener future with hydrogen-compatible boilers, however, there are even more sustainable options currently on the market.

If you want to reduce your carbon footprint further, we recommend also considering solar pv panels, biomass boilers, and heat pumps. You can even use heat pumps in conjunction with a system boiler in order to get the best of both worlds.

With all the different types of costs associated with getting a new boiler, it can be overwhelming to say the least. That’s where GreenMatch comes in. We can provide you with up to 3 free quotes, meaning you can easily compare prices side by side and don’t have to waste your time and effort figuring out which installers are worth contacting. Simply click the button below to get started.