From the greenspacelive site:
gModeller is an energy analysis plugin for Google SketchUp. Based on the gbXML standard for designing resource efficient buildings and specifying associated equipment, gModeller enables the building designer to decorate 3D SketchUp building models with gbXML surfaces and openings, to identify and label gbXML spaces, and to import and export gbXML models.
As a result of using gModeller, Google SketchUp becomes an intelligent solution for low carbon building design. Models can be quickly exported to gEnergyEPC for energy analysis and certification.
[ gModeller ]