The exterior façade, which serves as a second skin for the offices on the northern side of the building, enables natural ventilation, which both increases the feeling of comfort and cuts back energy consumption. The building can make direct use of the outside air: no other facilities are required besides windows that need to be opened and registers. In addition to the buffer areas in the building’s shell, the design outlines an atrium between the two naves that also functions as a buffer area. How it functions exactly depends on what the situation is in the summer or the winter. In the summer, the atrium serves as the cool heart of the building. The homes and offices can be naturally ventilated from this cool atrium. In the winter on the other hand, the atrium, combined with the building’s double façade, serves as a heat shell, limiting the loss of heat from the offices and homes. Where necessary, the buffer zones will be heated using heat from the geothermal storage system. The temperature in the intermediate zone is comfortable for a far longer time when air is used directly from outside. The stack effect results in a natural circulation of air. Using these facilities, the energy used for ventilation is reduced by some 75%.