Together with the Thuringian Housing Association (VWT), planners have developed a concept for the energy-efficient refurbishment of mass-produced residential buildings from the 1980s. This is being tested in a prefabricated GDR building owned by the Stadtroda housing association in Stadtroda, a small town in Thuringia. Among other things, the GDR panel building is to receive a new type of heat exchanger by 2023....