Combi? Open vent? System? What does it all mean?

Deciding on which boiler’s the right one for you isn’t always that easy. It’s not just a question of replacing one boiler with another, because your needs may change over time. Your installer will be able to advise you on the best heating and hot water solution for your home, but here’s a brief outline of the benefits of the three boiler types:

Combi boiler

This combines a high-efficiency water heater with a central heating boiler in a single compact unit. Hot water is supplied direct from the boiler, so there’s no need for a hot water cylinder in the airing cupboard or loft, making it the ideal solution for a home with limited space. And, as combis only heat the water as it’s needed, it’s an economical way of enjoying a constant supply of hot water.

Check out the Xclusive, Eco RF, HRE, Rapid and Rapid Plus models.

Open-vent boiler

An open-vent, also known as a ‘conventional’ or ‘regular’, is a
heat-only boiler that has no integral pump or expansion vessel. It is
specifically designed for the replacement market, where there is a
cold water storage tank (usually installed in the loft). This boiler is
recommended for larger homes with multiple bathrooms
and is used with an open-vented hot water cylinder.

Check out the HRE OV models.

System boiler

A system boiler is a heat-only boiler that has a built-in pump and
expansion vessel. This boiler is usually recommended for larger
homes with multiple bathrooms and is often used with an unvented
hot water cylinder to manage the higher demands on hot water.
System boilers are a little different to open-vent boilers as they get
their water supply direct from the mains, which is then stored in the
hot water cylinder so there’s no need for a cold water storage tank.

Check out the HRE SB models.