The German Energy Savings Act (Energieeinsparverordnung) requires sellers on the housing market to provide detailed information on expected yearly energy consumption per square meter. This paper uses variation of energy use and heating costs from local fuel prices, climatic conditions, and fuel types to analyze the relationship between expected energy cost savings from energy efficient building structure and house prices in a data set of listing prices from all regions of Germany. Furthermore, the role of building age for the value of energy efficiency is considered. Results suggest that agents are aware of the investment dimension of energy efficiency improvements, but not all important aspects are taken into account.