Today, Building Energy Performance Simulation (BEPS) analysis tends to show a large discrepancy with real energy performance. Most cases are due to gross mistakes rather than fundamental inadequacy of available technology and methods. The reasons are manifold. Highly simplified calculation methods are used far beyond their domain of validity. Assumed boundary conditions such as occupant behaviour are not in accordance with actual usage; gross malfunctions in control and HVAC systems are left undetected in the commissioning process, while thermal bridges and distribution system losses are left without attention. Moreover, metered and sub-metered data are not used efficiently in calculation tools and engineering based simulation models during the Measurement and Verification (M&V) phase.TRIBUTE aims at minimizing the gap between computed and measured energy performances through the improvement of the predictive capability of a state-of-the-art commercial BEPS. TRIBUTE will extend the use of this tool to the commissioning and operation stages of a building. For existing buildings, M&V techniques will be developed and deployed to connect the BEPS model in real time to the pivotal wireless sensing and control systems of a monitored building. This involves modelling building systems to a higher fidelity than done today, developing technology for on-line identification of building key parameters, and automatically adapting the on-line, real time BEPS to the actual building’s state.In addition, BHM and EFM application will compare measured data to the then improved predicted metrics and will enable detecting building deviations. Advanced data mining methods will help evaluate these deviations. Subsequent Energy Efficiency Diagnostic Rules and optimization methods will provide cost effective and corrective retrofit actions accordingly.The methodology and tools will be evaluated in the context of three different building types and locations.