A combi / combination boiler is a single, compact unit that’s designed to provide both central heating and hot-water. Ideal for saving space, this boiler is designed to heat water immediately, rather than heating and storing. There is no need for a bulky hot water storage cylinder or cold-water storage tank, as usually found with Heat Only systems and System Boilers.
With a System boiler, the majority of the components required for generating heating and hot water are built into the boiler.
The only external part required is a cylinder that stores hot water. Water is supplied directly from the mains.
A System boiler eliminate the need for a tank in the loft, that would otherwise be needed with a Regular Heat Only boiler.
Conventional or Heat Only boilers tend to be found in older properties but they can still be a great boiler choice for modern homes that have a high demand for hot water or a large number of bathrooms. As these systems require a hot water cylinder and cold water tank they may not be suitable for smaller properties. It’s important to keep in mind that with a conventional boiler you will not be able to get instant hot water. Instead you will need to program your thermostat to heat the water in advance ready for use later on.