In Voorburg (NL) 120 apartments in three buildings insulated with polystyrene won the national renovation price under the durability category. The prize is awarded for projects that set examples in energy efficient renovation, where durability has been specifically adressed, and where the architectural outlook has improved significantly. The energy rating on the dwellings was taken from class F (the lowest class) to class A (top class) due to the application of an external thermal insulation composite system (ETICS) comprising a polystyrene, which was developed by Gerard Smits from Dow. The insulation system with tiles was jointly developed and tested in Dow's technical center in Rheinmuenster according European Technical Approval Guideline ETAG 004, and all tests were passed successfully.