In October 2009, construction commenced on one of the largest Passive House developments globally, encompassing 1,700 flats across 100,000 square meters. This ambitious project, situated on a 20-hectare former railway site in Vienna, was initiated in response to a municipal mandate that mandated Passive House standards. Seven developers submitted their plans for multi-story buildings, each aiming for heating energy demands ranging from 7 to 15 kWh/m², in alignment with the provided urban masterplan.
Volume 1 of the architectural design stands out with its elegant elevation, creating a striking corner due to its towering presence and innovative design. This particular structure enhances urban connectivity, establishing pedestrian pathways between internal courtyards and public green spaces. Furthermore, the building’s configuration maximizes natural light for every apartment with openings spanning the entire height of the building. These “fugen” also provide spatial tension to the ensemble. Elevated housing is achieved by the reset base floor, with glazed community areas, including a playroom for children, bicycle storage, and kinderwagen storage, situated there.
Each flat enjoys its private outdoor space, and the floor-to-ceiling glazing and surrounding loggias seamlessly connect the indoor and outdoor areas. While apartment designs may vary, there is a distinct emphasis on ensuring that each unit is of equal value.
In the central courtyard, vertical ropes are strung to support climbing plants that grow upwards, reaching even the highest floors. Despite the presence of an underground garage and relatively shallow soil covering, the result is a vibrant and verdant courtyard.
The ecological achievement of this project lies in its exceptional thermal performance. Insulation ranging from 30 to 40 cm with enhanced thermal conductivity lines the exteriors and roofs, minimizing energy loss. The use of triple-glazed passive house windows ensures superior insulation, and clever design choices circumvent thermal bridges, which are often weak points in construction. With these measures, the Passive House standard is guaranteed, maintaining threshold values for the heating demand of 15 W/m²K and the heating load of 10 W/m², ensuring a significant reduction in CO2 emissions.
Architect: Dietmar Feichtinger Architectes
Structural Consultant: Vasko & Partner