If you are in the market for a new boiler or replacing an old one, you may have come across the term “system boiler”. But what is a system boiler, and how does it differ from other types of boilers? In this article, we will provide you with a comprehensive guide to system boilers, including their features, benefits, and drawbacks.
The Definition of a System Boiler:
A system boiler, also known as a sealed system boiler, is a type of central heating boiler that is installed in a closed system. Unlike a regular boiler that requires a separate hot water cylinder, a system boiler has all the components built into the unit itself.
System boilers are designed to work with a pressurized hot water cylinder, which stores and supplies hot water to the taps and shower in your home. This means that you can enjoy hot water at high pressure without the need for an additional pump.
These boilers are smaller than a typical boiler but may still provide a lot of household hot water.
Do you require a boiler that can produce plenty of hot water quickly? You could find a system boiler to be the best choice.
How Does a System Boiler Work?
A system boiler works by heating water in a central heating system, which is then stored in a hot water cylinder for use when required. The water is heated by a heat exchanger that is connected to the boiler, and the hot water is circulated through the central heating system via a pump.
When hot water is required, the water from the hot water cylinder is fed into the taps or shower at high pressure, providing you with a constant supply of hot water on demand. The system is pressurized, which means that the hot water is delivered at high pressure without the need for an additional pump.
Benefits of a System Boiler
There are several benefits to choosing a system boiler over other types of boilers, including:
- High water pressure: System boilers provide high water pressure, which means that you can enjoy a powerful shower or bath without the need for a separate pump.
- Space-saving: System boilers are compact and do not require a separate hot water cylinder, which means that they take up less space in your home.
- Easy installation: System boilers are relatively easy to install, and the components are all built into the unit, which makes installation quicker and more straightforward.
- Energy-efficient: System boilers are more energy-efficient than regular boilers, as they only heat the amount of water that is required, rather than heating a whole cylinder of water.
Drawbacks of a System Boiler
There are also some drawbacks to choosing a system boiler, including:
- Cost: System boilers can be more expensive to purchase and install than regular boilers.
- Limited hot water supply: The amount of hot water available is limited by the size of the hot water cylinder, which means that if you have a large family, you may need to wait for the water to heat up.
- Space for hot water cylinder: You will need space to accommodate a hot water cylinder, which may be a problem if you have limited space in your home.
System Boilers Vs Combi Boilers
| System Boilers | Combi Boilers |
| Requires a hot water cylinder to store and supply hot water | Does not require a hot water cylinder, as it heats water on demand |
| Provides high water pressure without the need for an additional pump | Water pressure may be lower, or a separate pump may be required for high water pressure |
| Suited for larger homes with multiple bathrooms | Suited for smaller homes with one bathroom |
| Takes up more space in the home, as a hot water cylinder is required | Takes up less space, as there is no need for a hot water cylinder |
| Can provide hot water to multiple outlets simultaneously | May struggle to provide hot water to multiple outlets simultaneously |
| Can be more expensive to purchase and install | Can be less expensive to purchase and install |
| Energy-efficient, as only the required amount of water is heated | Energy-efficient, as it heats water on demand |
| Requires regular maintenance to ensure that the hot water cylinder is functioning properly | Requires regular maintenance to ensure that the heating system is functioning properly |
Both system boilers and combi boilers have their advantages and disadvantages, and the best option for your home will depend on your specific needs and preferences.
How do a system boiler and a combi boiler differ from one another?
Your heating and hot water are provided by a single, space-saving boiler known as a “combination” or “combi” boiler. When space restrictions prevent the installation of a header tank or separate hot water tank, they are frequently a wise choice for apartments and family homes.
Combi boilers, however, have some drawbacks. They are particularly unsuitable for homes with high hot water demands because they can only support one outlet at once. Due to combi boilers’ tendency to switch the burner from heating to producing hot water when necessary, heating performance may also be affected.
As opposed to a regular boiler, a system boiler has a separate cylinder for hot water storage. The main elements of the heating and hot water system are integrated into the boiler, but the hot water is stored in the cylinder. This implies that a substantial number of faucets and showers may be simultaneously supplied with a steady supply of hot water. Because of this, it is the best option for a house with several bathrooms.
Are system boilers the same as conventional boilers?
It is simple to confuse a system boiler with a standard boiler due to the separate hot water storage cylinder (also commonly known as a conventional boiler). There are, nevertheless, some key distinctions. A system boiler is a sealed system that just needs a boiler and a cylinder, but a typical boiler could also need header tanks in the attic to feed the hot water cylinder and keep the radiators’ water levels constant.
Because of this, system boilers are frequently the best option unless there are particular circumstances where a conventional boiler may be more appropriate, such as in locations with low water pressure or in residences with outdated radiator systems.
How much room does a system boiler need?
Having enough space is one of the most crucial factors to take into account when selecting a system boiler because, in general, they are a little larger than regular boilers because they include an expansion tank and pump. Furthermore, the manufacturer’s warranty will typically cover the extra parts, which is a benefit. Typically, the hot water cylinder would be installed in the airing cupboard if your home has one it was built with one.
System boilers can be used in homes with no loft space, those that have undergone a loft conversion, or those that have an attic because they do not need header tanks installed there.
What is the efficiency of system boilers?
The boiler itself is quite efficient using condensing technology, with many models attaining up to 90% efficiency under ideal circumstances. A system boiler can also assist in optimising the amount of water used in your house because all faucets and showers will get nearly immediate hot water at the same pressure. The four-pipe design makes Viessmann system boilers unique from those made by other manufacturers. As a result, high-efficiency heating systems may easily apply weather correction.
We covered what is “condensing technology” on our page what is a combi boiler?
Can hot water run out in a system boiler?
The capacity of the hot water cylinder is the only restriction on how much hot water a system boiler can provide. It is advised that while measuring your cylinder, you take into account how much water is likely to be consumed at any given moment for things like showers, baths, and faucets in order to ensure there is always enough available. Be careful, though, that often the size of the cylinder you select will be determined by the available space. If designed properly, you shouldn’t run out of hot water. Your heating expert will be able to build the system and hot water tank to suit the household’s needs.
A storage combi boiler is something to think about if space is an issue.
What are the benefits of a system boiler?
It should come as no surprise that installing a system boiler has several advantages:
Installation is simpler.
A system boiler installation may be simpler, faster, and cleaner than a conventional installation. This is because a system boiler incorporates a large number of separate parts of the heating and hot water system.
Very useful for high hot water demand
Because hot water is kept in a cylinder, you may run several faucets at once without the pressure dropping. It is therefore perfect for houses with many bathrooms that are busy or huge.
Fast and Saves you money
System boilers include a pump, which makes them more responsive and cost-effective to operate. It can save money on your energy bills and more
Click here – to find out how to save money on your energy bills
It’s suitable for solar thermal
A system boiler is something to think about if using solar energy for hot water generation is a top priority for you. It is possible to modify the unvented hot water storage cylinder to heat water using solar energy.
Things to consider before having a system boiler
Before having a system boiler built, keep the following things in mind:
System boilers may use more room.
System boilers actually take up more room than combi boilers, despite the fact that a cold water feed tank is not required. This is because a hot water storage cylinder is required.
Size of a hot water cylinder
The size of your cylinder will determine how much hot water you can utilise. When the water in the cylinder runs out, you must wait for additional warm water. Depending on the model, this procedure might often take between 20 and 30 minutes.
It takes time to get hot water.
When a lot of hot water is consumed, the hot water may run out since it is kept in a storage cylinder with a limited capacity. Before your house receives hot water once more, the system boiler will need to heat additional water and fill the cylinder.
Costs for system boilers
Costs for replacing a blink boiler
The manufacturer and model have a big impact on price. When comparing the prospective costs of all accessible gas system boilers, costs might range from $500 to almost $2,000.
Models made by Baxi and Worcester Bosch are often the most affordable of the top system boilers we suggest. Both the Baxi 800 and Worcester Bosch Greenstar I ranges start at about £900 in price. The Vitodens 200-W series, made by Viessmann, is the most costly of these system boilers, with costs averaging £1,500.
Prices for system boilers are shown in the table below, however, they only include the cost of the boiler itself, not installation. If a hot water storage cylinder is required,
Price of installation
You should also keep in mind the installation charges in addition to the costs of system boilers. Numerous factors, such as the following, may have an effect.
- The installation’s level of difficulty
- Charges by the Installer for Accessibility
- Your residence (boiler installations could be more costly in London, for example)
It will typically cost between £800 and £1,500 to install a new system boiler. The cost of the top system boilers, including installation, is displayed in the table below.
A system boiler installation may take one to three days, depending on its difficulty. A like-for-like replacement is the system boiler installation method that is the quickest and easiest to do. When a different kind of heating system is being replaced, the installation will take longer. For instance, rerouting the plumbing and adding a hot water cylinder would be required to convert a combi boiler to a system boiler. If you intend to relocate the boiler, installation time will also rise.
Adding immersion heater to a system boiler tank
Integrating an immersion heater into a system boiler tank is a practical choice, offering enhanced versatility and reliability in hot water access.
This addition serves as an independent source of water heating, ensuring a continuous supply even when the main heating system is inactive due to breakdowns or servicing. It acts as a valuable backup, providing consistent hot water availability during unforeseen disruptions.
Moreover, the immersion heater allows for independent control of hot water, enabling selective heating without engaging the entire boiler system and potentially leading to increased energy efficiency. Overall, this modification provides a flexible and reliable solution for maintaining a consistent hot water supply in various circumstances.
Choosing the best installer for a system boiler
A new system boiler is an expensive purchase, so you’ll want the installation to be done expertly by a qualified contractor. A Gas Safe registered engineer must install a gas-fired system boiler (an OFTEC technician is needed for the installation of oil boilers).
We strongly advise comparing at least 3 quotes from several firms rather than taking the first one you are given. Finding the most qualified installation with the best price will be easier if you take the time to compare quotations.
You’ll receive free quotations for the installation of a new system boiler when you fill out our short online form right now. Each organisation we pair you with will give you a call once you submit the form.
