The combination of a heat pump with a wood-burning fireplace or pellet stove and an additional photovoltaic system represents a sustainable modern heating technology. This new type of hybrid heating system can be used in both new and existing buildings.

The HKI working group "Hybrid Heating Technology 2.0", among others, is working on the interaction of these different technologies in conjunction with well-matched interfaces. In a hybrid system, heat and hot water are supplied via a combination of different heat generators. Both systems complement each other optimally: an air source heat pump extracts the available heat from the outside air and converts it into heating energy. Its performance depends on the ambient temperature. This means that an air source heat pump has to work harder at sub-zero temperatures and cold air, whereby the efficiency decreases. At this point, the stove or fireplace with or without water-bearing parts is the perfect backup to compensate for the temporary "efficiency weakness" of the air-to-water heat pump. The wood fire minimises the extreme operating conditions of a heat pump, reduces its electricity consumption and additionally prevents premature wear of the pump.

Another goal of the HKI working group: to position this topic area more strongly in the public and to make it more accessible as a future-oriented building technology to the respective interest groups such as energy consultants, planners, architects, tradesmen and building owners, as well as to politicians and environmental associations.