Energie Steiermark HeadquartersRealized

Built in 1961, the corporate headquarters for the Energie Steiermark company in Graz found themselves in a situation that fell short of the company’s need to be a role model with regard to economical energy consumption. The question of ‘renovate or demolish?’ which arises so often with buildings of this era produced a study for the renovation of the elongated, nine-storey building, and recommended an extension to meet additional spatial requirements.

Rather than adding a low extension on the plot, Ernst Giselbrecht decided to elongate the existing building with extensions on both sides and of the full height of the building, although only the southern side was eventually constructed. This solution had organisational, energy efficiency and technical advantages: a very compact building only has short distances to travel and allows for clear organisation; the additional third staircase elegantly solved the existing building’s fire safety
problems; and the compactness provided a basis for significant improvements to energy efficiency. In addition, this design also allowed the construction of a park for employees and neighbours with underground car parking. Above all, however, the final building created a new whole which shows a clear presence in the city – not unimportant for a large company.

An additional layer of insulation covers the extended building; the insulation itself is covered with glass panels. Large areas of the southern and western facades have integrated photovoltaic and solar elements in the parapet areas, while the windows are covered by perforated shutter elements that act as sun and weather protection for the new windows, and as a climate buffer. A special feature is the daylight control using additional mirrored windows in the embrasure of the lintel area, which reflect light deep into the offices. They can be supported by LED lamps, so that they display an effect externally during darkness and play across the facade using colour control. There is also colour indoors, whereby unique colours are assigned to the floors to help with orientation.

Overall, the extension and use of the restored tenth floor, with a generous, column-free conference room, increases the useable floor space by around half, while at the same time reducing the overall heating requirement by around two thirds.

(Text: DI Martin Grabner)