This video shows the interface between Revit and the thermal simulation software ArchiPHYSIK from A-NULL Bauphysik GmbH. ArchiPHYSIK is a popular simulation tool in Austria and the other German speaking countries.

ArchPHYSIK works also with SketchUP and ArchiCAD; You can find out more on their Youtube channel:

http://www.youtube.com/user/archiphysik