CUBITY is the first modular residential cluster for students worldwide that meets an energy-plus standard. This innovative spatial concept is based on a house-within-a-house principle, with very minimized individual rooms and maximized communal areas with different temperature zones under one roof. It therefore enables transitions from the individual to the communal, from the small to the large, from the whole to the divided-as a synthesis of the key motifs cube, city, and community. The publication documents various stages of the development of the spatial concept at the architecture faculty of TU Darmstadt, as well as the presentation at Solar Decathlon Europe 2014 in Versailles. CUBITY provides exemplary solutions for sociological and energy issues and combines contemporary forms of communal living with sustainability aspects.