His most outstanding works have been focused on solar and low-energy buildings, which achieved extremely low energy consumption values. The first extreme solar house, completed in 1985, only needed 15 kw/m2*a for space heating. His work with developing methods of building affordable low energy housing brought him several awards beginning with the Binding Award for Environmental Conservation, 1989, and culminating in the Austrian State Award for Energy Research in 1997. The architectural design is clear and simple and frequently shows signs of his Scandinavian heritage.