Solar Decathlon Europe as a living laboratory for integrated climate mitigation and adaptation in the built environment

Solar Decathlon Europe (SDE) provides a full-scale experimental environment in which universities, industry and public institutions design, build and operate solar-powered and climate-responsive buildings. This study examines five completed European editions—Madrid 2010 and 2012, Versailles 2014, Szentendre 2019 and Wuppertal 2021/22—as a living laboratory for integrated climate mitigation and adaptation in the built environment. Evidence from competition documents, technical publications, three participant surveys and stakeholder interviews is analyzed through a framework comprising five dimensions: demand reduction, solar-energy supply, climate adaptation, occupant well-being and transfer capacity. The results show a progressive shift from stand-alone energy self-sufficient houses towards renovation, urban infill, vertical extensions, neighborhood integration and responses to climatic and societal vulnerability. The Wuppertal edition consolidated this urban transition by focusing explicitly on climate-neutral transformation of existing cities and by extending selected prototypes into the Living Lab Renania del Norte-Westfalia (Living Lab NRW). Across the editions, passive design, adaptive solar control, daylighting, photovoltaic and solar-thermal integration, thermal storage, passive cooling and building energy management were combined rather than treated as isolated technologies. Several solutions delivered dual benefits: façades simultaneously controlled solar gains and generated electricity; thermal storage reduced peak demand while supporting comfort; and climate-responsive envelopes balanced daylight availability, overheating protection and user control. The findings demonstrate the value of university competitions as living laboratories for climate action and identify the need for consistent metrics capable of evaluating mitigation, adaptation and human outcomes together.