A combination boiler, also known as a combi boiler, is a type of boiler that combines both a water heater and a central heating system in one unit. It is the most popular type of boiler in the UK, as it provides both hot water and central heating from one compact unit. The combi boiler is a highly efficient system that can provide hot water on demand, as well as a constant supply of hot water for your central heating system. It is also a great space saver, as it does not require a separate hot water cylinder or cold water storage tank. The combi boiler is a great choice for those who want to save energy and money, as it is highly efficient and can provide hot water and central heating at the same time. It is also a great choice for those who are looking for a reliable and efficient heating system.