The research project will evaluate the added value of dynamic thermal simulation models in the operational phase of a building: Final commissioning of low energy buildings Optimisation of the operation of low energy buildings Detection and diagnosis of faults in low energy buildings Therefore, the approach is implemented for 2 office buildings (one in South China and one in Belgium) whose research partners have access to BEMS (Building Energy Management System) data. Testing at two locations where climatic conditions and building construction standards/practices vary should provide a better understanding of the analysis. On the Chinese side, if there is no suitable building fully equipped with BEMS, another building with suitable measuring equipment will be used.