The aim of this issue of A+BE is to create a deeper understanding of the current rise of co-housing in Europe, and what it could mean in urban policies addressing energy transition and climate change. Studying co-housing is timely because the residents' associations become 'prosumers'; uniting the supply (production) and demand (consumption) of energy, housing and services in their projects. As such, they are increasingly seen as partners in the co-creation and maintenance of urban space.The study contributes to the emerging body of knowledge with a new understanding of co-housing, analysing its 'key-features' with an interdisciplinary framework, in a European context. It adds a new perspective to existing co-housing research, which is dominated by social sciences, by drawing attention to the physical characteristics of co-housing, produced in architectural, planning and engineering processes (the technosphere).