Biomass boilers work by burning biological matter and outputting the resulting heat for use in heating systems. Wood pellets, chips, logs or other biological materials are fed – automatically, semi-automatically, or by hand – into a combustion chamber where they are ignited. The hot gas and air produced by this process travel through a flue, and are then passed through a heat exchanger, which transfers the heat to the water used in the property’s central heating system. The excess heat is also stored in a thermal tank (also called a buffer vessel).

Biomass boilers can usually easily be integrated with existing space, under floor and water heating systems.