The most common type of boiler in the UK. Combi boilers take their water directly from the mains water supply, and heat it as required by your taps/showers and heating system, meaning there is no need for large water tanks in the home
Work in a similar way to combi boilers as they take their water from the mains storage system, but then store their hot water in a separate storage tank in order to provide instant hot water. They are the ideal option for larger homes with a high hot water demand.
A regular boiler is the oldest type of boiler system available and works by drawing its hot water from a large cold water tank in the loft or attic, heating that in the boiler, and then delivering that hot water to a hot water storage tank.