Choosing the right boiler.
A combi (or combination) boiler provides heat for central heating and heats water instantly whenever a hot tap or shower is turned on. Water is fed from the mains, so the water pressure is generally better than with traditional boilers and there’s no need for a tank in the loft.
Condensing combi boilers are the most popular type of boiler in the UK. They’re reliable, convenient and easy to install.
A system boiler is a boiler that directly heats your central heating system and hot water for a storage cylinder, whether itʼs an unvented, stainless steel cylinder or a traditional copper cylinder.
Most of the important parts of the hot water and heating system, such as the pump and expansion vessel, are built in on a system boiler – making it quicker and cleaner to install.
It also means you get a faster response to demand for heating and hot water, plus you donʼt need to have a feed and expansion tank in the loft.
Heat only boilers are also known as open vent, conventional or regular boilers. They heat your central heating and hot water when installed as part of a heating system together with a hot water storage cylinder, cold water storage tank, plus a feed and expansion tank. This is usually stored in the loft above the boiler to provide a good head of water.
If the boiler youʼre replacing is very old, it is most likely a heat only boiler. One of the other clues is that youʼll have a separate circulating pump, instead of one inside the boiler.