As a research partner, EA Systems is working in cooperation with the TU Dresden and other partners on a standardization of tools and programs for the design and evaluation of complex building energy supply systems. The prototypical implementation of coupling possibilities based on the Functional Mockup Interface Standard (FMI) significantly contributes to the communication between planners, architects, clients and engineers. In this way, the advantages of different tools are to be consolidated in order to create a uniform, standardisable framework for the design and planning process.