The KfW Westarkade is a prototypical ecological building, one of the greenest office structures in the world. This fifteen-storey extension to the KfW Group’s headquarters complements their varied ensemble of existing administrative buildings. In addition to housing a conference centre, it provides office space for 700 employees.

Despite its height of 56 metres, the new tower fits in with the cluster of existing towers without blocking their views. Its idiosyncratically sculpted form and subtly varied polychromatic treatment help it to mediate between two distinct urban realms: while appearing as a slim slab from the busy street, it presents a discreet backdrop to the greenery of the Palmengarten botanical garden. The flowing form of the four-storeyed plinth picks up the eaves height of the neighbouring buildings and defines the edge of the street, counterpointed by a gently concave recess that marks the entrance.

The wind-pressurised double-skin façade was devised especially for this building – whose streamlined form facilitates its efficacy. The façade guarantees natural ventilation regardless of the weather, combined with high insulation performance and efficient solar screening. Radiant floor slabs, geothermal heating and the recovery of waste heat from the central IT systems are among the coordinated measures that contribute to the building’s low energy consumption. The KfW Westarkade was voted “Best Tall Building Worldwide” for 2011 by the Council on Tall Buildings and Urban Habitat.