The overall target of the Swiss Energy Policy is to reduce CO2-emissions and thereby to achieve the vision of an energy-efficient ‘2000 Watt per Capita Society’. A major instrument to contribute to the vision in the residential building sector is standards about energy-efficient building designs. However, new residual houses according to the energy-efficiency standard are not as often constructed as they ought to be. This short-term decision has a long-term consequence. In this paper, a preliminary System Dynamics model about the system ‘residential building environment’ will be presented with the purpose to explain the development of key variables of the building environment system. The analysis of possible policies put forward that a sound understanding of the decision process of potential building owners is necessary to create a beneficial system design which foster the diffusion of energy-efficient building designs. Furthermore, the paper should enable discussions about the model and methodological issues of the model creation process.