September 21, 2021

What Is A System Boiler?

A system boiler is a kind of boiler that is typically seen in bigger houses with higher heating and hot water needs. System boilers, as opposed to combi boilers, have a separate storage cylinder that allows them to deliver hot water on demand throughout the house.


How do system boilers work?

Combi boilers are linked to the cold mains, while system boilers are not. It is possible to send heated water to many faucets and showers at once by using a coil in the cylinder. This coil transports hot central heating water through the cylinder, heating its contents. They are able to heat the cylinder and both radiators at the same time, so there is no loss of comfort.


Is a system boiler the same as a standard boiler?

There are some parallels between system boilers and traditional boilers, but there are also some key distinctions.
Boilers that store hot water for later use, often known as conventional or heat-only boilers, work similarly to system boilers. As a consequence, they’re more common in older, bigger houses.
In contrast to conventional boilers, which utilise a header tank in the loft (also known as a feed and expansion tank) to artificially maintain pressure, system boilers employ a pressurised heating circuit filled up with city water.
To keep the water pressure constant, they utilise an exterior expansion vessel. In contrast, the expansion vessel in a system boiler is usually internal. As a result, system boilers are increasingly popular in contemporary homes with numerous bathrooms since regular boilers take up more area and sometimes require more complicated plumbing.


Is there a difference between a system boiler and a combination boiler?

Combi boilers only heat water when you need it, whereas system boilers store hot water in a cylinder for later use. Because of its compact form, a combi boiler has an advantage over a system boiler for residences with limited space, such as terraced houses and flats.
Combi or system boilers? That depends on your household’s heating and hot water demands. Because a one-bedroom, one-bathroom house uses less hot water than a three-bedroom home, a combi boiler makes sense.
Combi boilers, on the other hand, will be unable to satisfy the demands of bigger homes due to the restricted quantity of water that can be heated on demand. However, system boilers can retain hot water for a longer length of time and better handle the hot water needs of multiple radiators, faucets, and shower heads in a home or business.
Read more on the differences between the various boiler types on our other blog.


What are the costs of a system boiler?

A system boiler may cost anywhere from £500 to £2000, depending on the type, size, and manufacturer.
An entry-level boiler is an excellent choice for houses in the middle of the range, with somewhat greater energy needs than homes with 1-2 bedrooms. Premium versions, which may cost up to £1500, are an excellent choice for households with high heating needs.


Advantages of a system boiler

Greater availability of hot water

When numerous showers, radiators, and faucets are in use at the same time, system boilers may save money by storing huge amounts of hot water that can be used later.


Acceptable as a fuel for solar power

You may use solar panels with system boilers as long as you attach the right cylinder. This may be a cost-effective and ecologically responsible method to heat your house.


It takes up less room than a conventional boiler.

System boilers, as opposed to conventional boilers, do not call for an expansion tank or external expansion vessels. As a result, they’re simpler to set up and take up less room.


Disadvantages to consider

In comparison to a combination boiler, more room is required

System boilers, because of the external cylinder, need more space than combi boilers, despite the fact that they take up less room. Consequently, installing them in a tiny house may be problematic. Check out our full guide on boiler sizes.


During busier periods, you may have to exercise some restraint

While your cylinder should have been designed to meet your regular use (usually about 50 litres of stored hot water per person), there may be occasions when usage is greater than normal because of guests, Christmas, etc. There will be a 30-40 minute delay if the cylinder capacity is exhausted during these periods.