What is a system boiler?

Most homes will have a ‘combi’ type boiler that will satisfy all their demands for central heating and hot water. For some larger homes, however, this type of boiler can struggle to provide all of the hot water and heating a home can need, especially if many people live in the home.

For these larger homes, a system boiler is a smarter choice. These can provide large amounts of consistently hot water, while also providing enough heat to warm many large rooms in a house. 

But what is a system boiler? How is it different from other types of boilers? Should I install a system boiler in my home? These are some of the questions we are going to answer for you so that you can make a more informed choice when you are replacing the hot water boiler in your home.

What types of boilers are there?

The vast majority of homes in the United Kingdom use a hot water boiler to provide central heating and hot water. Any boiler installation should be performed by qualified heating engineers to ensure the boiler is safe and works correctly.

Many homes have what is called a combination or ‘combi’ boiler. These are often installed in homes as they are very energy efficient in most situations. They provide central heating and hot water on demand from a single unit, which makes them a compact solution to home heating and hot water that can fit in a small space. 

Heat only boilers are becoming less common in homes, but can often still be found in older houses that have not been updated or renovated. These are sometimes called open-vent or regular boilers as they are not pressurised. These systems use a cold water tank to hold a large volume of water that feeds a smaller heating tank for the home’s central heating system. This type of boiler often struggles to supply consistent hot water, particularly in the winter months when there is high demand for home heating as well as hot water.

System boilers are similar to heat only boilers. They have a large water tank that stores hot water, ensuring there is a large supply of hot water ready to use which larger homes often need.

How does a system boiler work?

Unlike the ‘combi’ boilers that you will find in many homes, system boilers are not directly connected to the cold water mains supply. They have a large water tank or cylinder that holds water which is heated by an internal coil. This water can be heated while the boiler also supplies central heating through radiators. When the water is heated it is kept at a high temperature so there is enough to supply multiple showers or hot taps all at the same time. 

This is why they are a much better heating and hot water solution for large houses. In homes with multiple bathrooms and many occupants, regular boilers and combi boilers are not able to consistently supply every demand for hot water. Different types of boilers have different advantages.

How energy efficient are system boilers?

System boilers can be very energy efficient. Some have been able to achieve 90% energy efficiency under the best conditions, though this is often from boilers that use modern condensing technology. 

With a system boiler, all of the home’s hot water taps and showers can be supplied with nearly instantaneous hot water without a loss of pressure. This helps to optimise your home’s water usage, which can help to reduce your home’s consumption, and water bills. It also helps to add good water pressure if your home is in an area where the mains water supply is at low pressure. By having a regularly scheduled boiler service you can help keep your boiler working efficiently all year long.

Can a system boiler run out of hot water?

The biggest limit to the amount of hot water a system boiler can supply is the size of its cylinder or tank. If you are thinking about installing a system boiler in your home you should take some time to think about how much hot water you may need to use at any one time. This will help you to decide how big a cylinder you will need to install.

One of the biggest advantages to a system boiler is that you have a range of size options to choose from, which makes your central heating system scalable to meet your requirements. If you have a large property, with many hot water outlets and bathrooms, you can use a larger tank and system boiler to ensure an ample supply of hot water and heating whenever you need it. If you have boiler cover, you can have any problem with your system boiler solved quickly by a qualified heating engineer without added costs.

System boilers have a lot of advantages over other types of boilers, whether you have a large home or not. If you want a large and consistent supply of hot water in your home, from every tap and shower, then they may be the best option for you.

Invest in a new system boiler with toasti

With over 30 years of experience in new boiler installations and boiler replacements, including combi swaps and back boiler conversions, toasti is on hand to help you find the best new boiler for you and your home. 
It’s quick and easy to get a quote for a boiler replacement with toasti. Contact us today and one of the team will guide you through the process.