Boiler Types, Chichester

What are the different types of boiler?

What is the difference between Combination boilers, Conventional boilers and System boilers?

Combination boilers (combi boilers), conventional boilers (also known as traditional or regular boilers), and system boilers are three common types of boilers used for heating homes.

Here are the key differences between them:


Combination Boilers (Combi Boilers)

Functionality: Combis serve as both a central heating boiler and a water heater. They provide hot water on demand, eliminating the need for a separate hot water storage cylinder or tank.

Space: Compact and space-saving, as they don’t require a separate water storage tank.

Installation: Easier and quicker to install than conventional systems.

Pressure: Suitable for homes with low water pressure.

Pros: Efficient use of space, no need for a separate water tank, and on-demand hot water.


Conventional Boilers (Regular or Traditional Boilers):

Components: Consist of a boiler, a hot water storage tank, and an expansion tank in the attic. The system includes a cold water storage tank (usually in the loft) and a feed and expansion tank.

Hot Water: Hot water is stored in the cylinder and is ready for use whenever needed.

Installation: Requires more space and a loft for storage tanks.

Pressure: Typically works well in areas with higher water pressure.

Pros: Suitable for larger homes with multiple bathrooms, provides hot water to multiple outlets simultaneously.


System Boilers

Components: Include a boiler, expansion vessel, and a hot water storage cylinder, but no cold water tank in the loft. The heating and hot water components are built into the boiler unit.

Hot Water: Hot water is stored in a cylinder, providing a reservoir for domestic use.

Space: More space-efficient than conventional systems, as there is no need for a loft tank.

Installation: Easier installation compared to conventional boilers.

Pressure: Works well in areas with moderate water pressure.

Pros: Provides a constant supply of hot water and is suitable for homes with more than one bathroom.


In summary, the primary differences lie in the way these boilers handle hot water provision and storage.

Combination Boilers: Heat water on demand and do not require a separate storage tank.

Conventional Boilers: Use a separate hot water storage cylinder and often a cold water tank in the loft.

System Boilers: Have components for both heating and hot water built into the boiler, with a separate hot water storage cylinder but no cold water tank in the loft.

The choice between them depends on factors such as the size of the property, the number of bathrooms, available space, and the desired hot water delivery method. Our knowledge engineers are on hand to help and advise the right boiler you for you and your home, get in touch today!