The market potential of heat pumps for retrofitting existing buildings is much larger than in new buildings. However, the heat pump market in existing buildings today is small compared with the presently dominating market in new buildings. The new annex should therefore contribute to overcome the technical and market barriers in this interesting market sector.
The objective of annex is a survey of the availability, technology, economy, ecology and possible R&D trends of heat pump systems to retrofit low energy efficient space and tap water heating systems in existing residential buildings, taking into account that heat pumps are able to drastically reduce fossil energy consumption and the related greenhouse gas emissions. Space heating systems include first of all hydronic systems including heat sources, heat pumps and distribution systems but also air-to-air heat pump air-conditioners without heat distribution system. Heat pumps for retrofit should include electric heat pumps with zero or low GWP working fluids and gas-fired systems including ab- and adsorption.