The three-, four-story base construction is the foundation of an all  in all 56 meter high office tower, integrating a modern conference center as well as flexible office work places for 700 employees spread across 15 floors with a gross floor area of 40,000 square meters. Apart from the colorful design of the glass façade, tried and tested by Sauerbruch Hutton many times before, the focus for the new building standing right next to the already existing KfW headquarters, was on developing sustainable building technology.

Sustainable Building Concept

KfW supports the erection of energy efficient buildings by making use of many programs. So it’s no wonder that the bank group aimed at realizing their own new building with an “ecological footprint” as small as possible. In order to realize these specifications, Sauerbruch Hutton developed a special double-layer pressure-ring façade together with the company Transsolar to guarantee natural ventilation independent from the weather, a high thermal insulation value as well as an efficient sun protection. Thermo-active building systems, a geothermal heat exchanger, heat recovery and building control systems help reduce energy consumption even more. By pooling various measures, the new building is among the first office highrise buildings worldwide to have an annual primary energy requirement of below 100 kilowatt hours per square meter.

Colorful Shell

With that much of ground-breaking building technology, the striking architecture nearly takes a backseat. Apart from aero-dynamically curved shapes, enabling a flowing transition between the Palmengarten’s green belt to the North and the already existing KfW headquarters, especially the unusual design of the glass façade stands out. Since in order to place the flaps required for ventilation, the glass panels, inserted from and to end, protrude slightly towards the South, resulting in the façade’s fin-like look. The vertical glass panels taking turns with the colorfully painted panel edges create a moving play of colors, providing very different visual impressions depending on the viewing angle: Looked at from the North, the façade looks as if it was fully transparent, viewed from the South, however, it looks as if painted from end to end. In addition, the deployed colors change as well: Red and gray are dominant in the West, the South displays blue elements.

The dynamic design not only generates an advertising effect for KfW, it also provides an upgrade for the urban scenery, and it transports the ecological claims made by the bank group. A well-made symbiosis of architecture and building technology that shows that Sauerbruch Hutton are capable of much more than just planning nice buildings.