The current World situation is particularly complex and heavy, from many points of view, among which energy and socio-economic ones. The COVID-19 pandemic, besides causing a health crisis, has brought out, even more, the need to reduce emissions for a healthier environment. The role played by the existing building stock is fundamental, as it is responsible for 36% of CO2 emissions in Europe. The proposed work aims to define some energy refurbishment interventions, for a residential building in south Italy, regarding the building envelope, the heating and cooling systems, and the addition of systems from renewable energy sources in order to improve its energy labeling. The methodological approach has followed the guidelines for the energy certification of buildings in Italy. It was possible to evaluate the improvement in building energy labels according to the proposed efficiency measures, highlighting those which allow for a tax relief recently introduced by the Government. Finally, the addition of photovoltaic and solar collector systems was evaluated to allow even the fulfillment of nZEB standard.