Supporting public decision process in buildings energy retrofitting operations: the application of a Multiple Criteria Decision Aiding model to a case study in Southern Italy

The challenge of promoting sustainable cities and reaching the objectives developed by the European Green Deal includes the renovation of the building sector, as it is responsible for 40% of energy consumption In Europe. Regional or local public administrations have to allocate their financial resources for improving the energy performances of their building stock and to face a multidimensional problem, where different aspects - such as energy efficiency, financial-economic feasibility and environmental protection - have to be harmonized. The present study proposes a Multiple Criteria Decision Aiding model, which includes the ELECTRE TRI-nC method, for supporting the public decision process of sorting alternative energy retrofitting actions into various categories, each of them expresses different levels of overall performance. The model is applied to an Italian real case study. An experts’ panel has been involved for structuring the decision problem and discussing the results. The results show that opaque envelope insulation actions are often classified in best categories to be implemented and funded instead the upgrade of the lighting system falls in the worst category. These results are useful for local or regional public administrations to select those energy retrofitting actions that have to be financed as a priority.