A 'combi' boiler provides heating and hot water in one single compact unit, hence there's no requirement for an additional hot water cylinder as the water is heated instantaneously.

The hot water is also supplied at mains pressure which is a great benefit for providing a powerful shower.

Combi boilers are ideal for smaller properties, and the installations tend to be simpler and cheaper than system or regular boiler options.

System boilers have similarities to combi boilers, in the way that they both provide pressurised heating and hot water. However they are typically suited to larger properties with more than one bathroom and increased hot water demands. Consequently they require a hot water cylinder that provides a constant supply of pressurised hot water to multiple outlets. Additionally the installations are more complex and larger than combi boiler installations.

Regular boilers are suited to the traditional type of heating system, with a hot water cylinder and cold water storage tanks usually sited in the loft. A regular boiler is generally appropriate for larger properties with more than two bathrooms and therefore increased hot water demands. They are also ideal for properties with an older central heating system, which may not be able to sustain the higher water pressures of a combi or system boiler installation.