The "Casa en Casa 84" is a passive house inside a formerly listed warehouse introducing to its users an unconventional way of living. This experimental design approach complies with Poblenou's adaptive architectural regulations, as the current site's interior will be slightly revamped, showcasing its historical significance. The staggered arrangement of the interior envelope enriches the sense of movement within a rigid context, shaping an open-plan distribution and creating in-between spaces which overlook the courtyard. The surrounding vegetation functions as a buffer zone that guarantees its users' privacy, lowering the neighbour’s noise levels as well as filtering the indoor air quality. Last but not least, natural light will illuminate the interior space through skylights, openings and hollow partitions composing a natural ventilation system.