"The Austrian government project "Building of Tomorrow" supports research projects helpful for a social implementation of domestic and office energy saving concepts. Sustainable development will only work through the understanding and commitment of individual dwellers. In a post-occupancy evaluation with long field interviews, the author and his team studied opinions and self-reported behavior of 114 households in four energy-saving (E) and four conventional (C) housing estates of Salzburg City. There were only minor differences in sociodemografic variables (more children in E, higher operating costs in C)."