The design process of buildings and energy supply systems consists of several steps with increasing accuracy and decreasing fault tolerance. Because of a wide range of unknowns and increasing complexity, Modelica models are often an integral part of the first design steps. However, there are only rare updates and reuse of these models in later phases and/or during building use.This paper emphasizes the potential of a continuous update and use of available Modelica models during all steps of building design processes. It therefore regards an example of a research greenhouse building for which the initially developed Modelica models were continuously updated and reused during the final phase of intensive scientific monitoring. Furthermore, general insights in latest scientific approaches indicate suitable steps of partly-automated continuous model updates during the whole building life span using BIM (Building Information Modeling).