This study examines the use of building modeling and energy simulations in the design process of a building. The take-off point is the notion of energy simulations being needed early and throughout the building design process, and that the lack of energy simulations may be explained by the fact that they are time consuming and therefore often too expensive. A greater interoperability between software tools used by relevant disciplines, such as the architect and the energy specialist, would create smoother workflows, which would reduce this cost and open up for more frequent and iterative energy simulation processes. The study is an assessment of the modeling tool Revit and the simulation tool Virtual Environment and whether they can create smoother workflows, and make leeway for a more frequent use of energy simulations throughout the design process. It also investigates the limitations of what can be examined by simulations in Virtual Environment. This will hopefully help clarify the future role of energy simulations in design processes. The method is a trial by error approach of testing the two software tools by building and simulating a model. The results of these tests show that the workflow is not optimal (and therefore time consuming) for frequent and iterative simulations throughout the design process, but it also reveals some great possibilities of what can be performed with these two powerful tools at hand. Further development with regards on platform independency of the building information model, including seamless exporting and importing, seems necessary to strengthen the future role of energy simulations.