Energy Performance Contracts (EPC) are contractual agreements between beneficiaries and energy service providers, where budgets are established in relation to a determined level of energy performance. Hence, the problem of forecasting the energy performance of buildings in the EPC tendering phase becomes relevant for the reliability of the overall contract. Unfortunately, fuzziness and incompleteness often characterize the technical information supporting EPC call for tenders. Furthermore, buildings that are the subjects of EPCs are normally quite complex public buildings (hospitals, schools, etc.) usually relatively old and not technically well known. Gathering information about such buildings is a time consuming and expensive process within the usually short time frame of EPC call for tenders. This paper investigates the application of Grey-Box modelling to the energy performance forecast of complex buildings, in perfectly and poorly informed operational cases. The proposed methodology offers a potential solution to the EPC operational requirements since it requires a substantially reduced parameter set. Results show that the proposed Grey-Box modelling can be used to arrange a calibration set-up with good forecasting performance. Furthermore, Grey-Box modelling allows an effective management of the information uncertainty usually present in the EPC context
