In 1995, the German Federal Ministry of Economics and Technology launched an intensive research and demonstration program on energy optimized construction of new buildings as well as retrofitting the building stock (www.enob.info
). Beside material and component research, approximately 50 demonstration buildings have been realized and monitored, covering various building typologies. Accompanying research was conducted to keep track of the results and lessons learned. Many of the demonstration projects have reached energy savings of 50% and more compared to current practice in Germany, without exceeding conventional investment costs. A number of these projects have been awarded architectural prizes. This paper summarizes key findings and explain the strategies for new projects on the path to a net zero energy balance in the building sector. These strategies are based on a further decrease in energy demand and increased renewable energy utilization in conjunction with an intensified use of building integrated power generation with utility grid interaction.