GREENH@USE is a mixed-programme social housing building in Barcelona’s 22@ that treats climate comfort as both an environmental and a social project. Its main sustainability strategy is not an add-on system, but a thermodynamic section: a sequence of courtyards stitched together by an elevated “street” culminates in a covered atrium that works as a shared, tempered interior landscape. The atrium is a bioclimatic device with strong thermal inertia. In winter, roof skylights turn the glazed volume into a solar collector, storing heat in the prefabricated concrete structure and smoothing temperature swings so comfort is perceived as stable in both the dwellings and the common circulation spaces. In summer, the same volume becomes a solar chimney: buoyancy drives natural ventilation through patios and walkways, purging heat and improving air quality without mechanical dependency. Hygroscopic timber linings and acoustic patio finishes help keep this intermediate space comfortable to inhabit, not just to pass through. A naturally daylit and cross-ventilated parking level strengthens this passive logic while future-proofing the building. The garage is conceived as an adaptable space, and it also hosts generous air ducts that draw fresh air from a planted courtyard and feed the atrium—working like an earth-tempering “Canadian well” to support summer ventilation. Social sustainability is embedded in the environmental concept. Temporary accommodation sits at ground level, four floors of social rental housing above, and senior one-bedroom units on the upper levels with the best sun. Shared laundries, urban gardens, solarium and multipurpose rooms activate daily encounters, encouraging contact for older residents and enabling intergenerational exchange across the vertical mix. By combining thermal mass, solar gain, natural ventilation, solar protection and generous collective spaces, GREENH@USE reduces energy demand passively while expanding the everyday benefits of communal living.