In 2025, a comprehensive window and façade refurbishment was carried out in Courtyard 3 of the main building at Karlsplatz in collaboration with BIG. The inner sashes were fitted with modern insulating glass, whilst the outer sashes now feature high-quality solar protection glass. Combined with state-of-the-art sun protection systems, this results in a significant improvement in user comfort – more pleasant room temperatures, reduced glare and an overall improved indoor climate.

At the same time, these measures boost the energy efficiency of the entire building. The combination of optimised thermal insulation and effective protection against summer heat sustainably reduces energy consumption – an important contribution to resource-efficient operation and a rapid return on investment.

The refurbishment impressively demonstrates how listed buildings and modern building technology can be combined harmoniously. The result is a site equipped for the future, which will benefit both users and the environment in the long term.