Last updated on: 29 August 2024

What is a System Boiler? Everything You Need to Know

System boilers are the kind of boilers that fulfill the heating and hot water demands in larger homes. They are prevalent among UK homes with multiple bathrooms. The system boiler not only powers up your central heating system but also heats water and stores it in a separate storage tank to provide you with an uninterrupted supply of hot water for numerous showers, taps, and bathrooms, whenever you need it.

How does a system boiler work?

System boilers operate by getting connections directly from the mains and provide space by eliminating the need for a separate cold-water tank. It consists of a coil in the cylinder that transfers the hot water at a desirable temperature and pressure to multiple taps. In addition, the system boiler can heat your home’s radiators simultaneously.

What are the components of a system boiler?

If we discuss the components of a system boiler, there are only two: the boiler itself and an external storage tank. Everything else required to generate a continuous heating and hot water supply is integrated. Depending on your usage, you may need to refill the tank once or twice a day.

Is a system boiler better than a regular boiler, and how do they differ?

Many homeowners are confused about the differences between regular and system boilers. To clarify, these two types of boilers are somewhat similar to each other. Regular boilers require both hot water and a cold-water storage tank, with the cold water from the expansion tank being fed to the boiler to increase the pressure. When the boiler is fired up, the cold water is heated through a heat exchanger and stored in an external hot water tank for use when needed.

On the other hand, system boilers use a pressurised heating circuit that is directly connected to the mains. This type of boiler does not require an expansion tank as it is built-in, making it a more popular choice due to its space-saving design and lack of complex pipework compared to regular boilers.

Is a system boiler better than a combi boiler, and how do they differ?

If we compare system boilers vs combi boilers, the difference is clear: combi boilers don’t require an additional hot water tank. Combi boilers are a popular choice for smaller homes due to their cost-effectiveness, compact design, and ease of use. You get hot water on demand with a combi boiler, just like a system boiler, but you must program it first. Additionally, combi boilers require two heat exchangers, while system boilers only require one.

In conclusion, if you have a larger household size with 3–4 bathrooms and five or more people requiring hot water, a system boiler is the ideal choice. A combi boiler is the best option for 1-3 bathrooms and 1-4 people requiring hot water.

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System boiler advantages and disadvantages

Pros:

  • Get hot water on demand courtesy of a separate hot water tank, which stores the hot water in quantity to supply you with it when you need it.
  • You will be left with more space compared to regular boilers as System boilers don’t require a separate cold-water tank; it draws water directly from the mains.
  • You can get hot water in multiple bathrooms simultaneously at dense pressure and hot temperature.
  • System boilers are also energy efficient, as they can also work with solar thermal systems, lowering the cost of your energy bills.

Cons:

  • Eventually, the System boiler does occupy space. Although, as compared to regular boilers, they don’t require an additional cold-water storage tank but a hot-water tank. If you live in a relatively small home with little demand for hot water in larger quantities, then we advise you to get a combi-boiler.
  • Although you will be supplied with unlimited hot water on demand, you may use all the hot water and then wait for it to get heated, which will take some time, so you will need to program it in advance.
  • There is also a lot of possibility of your hot water getting wasted. As mentioned above, you will have to program it in advance. You often heat and store a lot of water that you might not use, resulting in water waste.
  • System boilers are ideal for hot water and heating delivery but require a very complex installation, maintenance, and service compared to combi boilers.

Cost of a System Boiler

The installation cost of a system boiler varies from manufacturer to manufacturer. Below we will tell you the cost you will have to pay for a new boiler of different manufacturing brands.

BrandSystem CostLabour CostInstallation TimeTotal Cost
Ideal£1,800 to £2,800£300 to £5006 to 12 hours£2100 to £3300
Baxi£800 to £1,200£300 to £5006 to 12 hours£1100 to £1700
Worcester Bosch£900 to £1,300£300 to £5006 to 12 hours£1200 to £1800
Vaillant£1,000 to £1,400£300 to £5006 to 12 hours£1300 to £1900
Viessman£1,100 to £3,000£300 to £5006 to 12 hours£1400 to £3500

Note: Original prices may vary depending on the manufacturer.

How much space does a system boiler need?

As previously mentioned, system boilers require ample space. Therefore, if you are relocating to a new home or replacing an old boiler with a new system boiler, leaving at least 60 cm of space around the boiler and 15-20 cm below and above it is recommended. For optimal performance, providing the system boiler with the necessary space is essential.

Is a system boiler expensive, and how long do system boilers last?

System boilers are cost-effective compared to heat-only regular boilers; apart from that, you will observe a significant drop in your energy bills when upgrading from a regular boiler to a system boiler. All said above is relevant until and unless you have a larger home with frequent hot water and heating usage. A combi-boiler is the ideal and most cost-effective choice if you have a smaller home with no frequent usage or demand for hot water and heating.

Now, if we talk about how long it lasts, then the average life span without any repair hassles is ten years, and if you maintain it annually, it might last up to 15 years.

How to make the most of your system boiler

Maintaining it annually and programming it according to your needs is essential. For instance, it is crucial not to store more or less hot water than you need, as storing too little may leave you without hot water when you need it, and storing too much can lead to energy and water wastage.

Conclusion:

After reading this article, we hope you know what a system boiler is and why you should buy one. To summarise what we have discussed so far, if you have a regular boiler and have a larger home with more demand for heating and hot water, then a system boiler is an ideal and cost-effective choice considering the efficiency rating, and if you have a smaller household with not that high a demand for hot water and heating needs, then combi-boiler is a perfect choice.

If you have any queries regarding your boiler and need some information, please get in touch with us at 0345 3192 247, as we are always there for your assistance.

Get a new boiler
today!

Get your new System boiler and save your heating bill yearly with new energy efficient boiler.

Get a Quote Now

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Posted by: Martin Astley 20 January 2023