In private households, it is predominantly single-room fire units, such as stoves, masonry heaters and tile stoves that are used for heating. In most cases they supplement the central heating system and are often only used occasionally. Around one million households in Germany have a wood-burning central heating facility (log gasification boiler, pellet heating, wood-chip heating, etc.), supplying all rooms with heating via the water-operated central heating system, and usually simultaneously heating the water used for other domestic purposes.
Today, thanks to technical progress, modern biomass installations – such as pellet stoves/pellet boilers, log gasification boilers, and wood chip heating – achieve efficiency grades that in many cases are already significantly over 90 percent. The technical development is remarkable: accordingly, modern installations are achieving efficiency grades around 20 percent higher than wood burning boilers installed 20–30 years ago!
Yet the further development and optimisation of combustion chambers and combustion systems, as well as of the control and adjustment of the combustion process used in stoves and boilers, has not solely led to greater efficiency in wood burning. Modern wood burning systems are characterised by very low emissions of particulate matter, carbon monoxide and nitrogen oxides. Legal regulations (Small Firing Installations Ordinance/ Kleinfeuerungsanlagenverordnung) order minimum efficiency grades and significantly stricter emission requirements for single room or single-area fire units.