In this thesis, the basics and possibilities of Building Information Modeling (BIM)-based building efficiency analyzes are presented and demonstrated using an existing building of the TU Darmstadt (L501). The currently valid climate policy targets concerning the building sector and their characteristic values are listed. The Building Information Modeling, its relevant terms and basics, and the current state of the implementation are explained. An overview of building efficiency analyzes and their technology is given. At this the current climate policy laws and regulations are shown, together with their static calculation bases. These are compared with the dynamic methods of BIM-based building efficiency analyzes and their advantages named. Furthermore the available data exchange formats and the general process of a BIM-based building efficiency analysis are presented. Based on the possibilities and functions of the BIM-based building efficiency analyzes, a concept is presented which explains the implementation of these analyzes into practice. It takes into account the phases of a construction project and the possible functions of the analyzes for a practical implementation. The questions when, how and under which criteria an implementation can take place are discussed. It was possible to find meaningful integrations of BIM-based building efficiency analyzes over almost the whole life cycle of a building. A small selection of commercial and open source software will illustrate different approaches. An application of a BIM-based building efficiency analysis is carried out on the basis of an existing building of the TU Darmstadt (L501), using the software Insight. The necessary work steps, basics and setting possibilities are shown here. The adjustments made for a realistic calculation are described. The focus is on a variant-development, which can be used for a possible renovation. The possible parameters of this variant are explained and their influence shown. The results of the variant-development show a significant improvement in energy costs /energy consump- tion values. Also shown are the views of the heating and cooling loads and the photovoltaic analysis. Furthermore the implementation of a daylight and solar analysis and their results are described. Possible barriers and obstacles of BIM-based building efficiency analyzes were discused. It provides an outlook on the future development potential of BIM-based building efficiency analyzes and their significance for new technologies (Internet of Things, smart grid).