In 2050, about 80% of the European building stock will consist of buildings currently in use. In Italy, a significant share of such stock was built during post-war reconstruction through the Ina Casa social housing programme, which solved such problems as unemployment and housing demand. The rationale behind the building focussed on tradition and saving and drove the implementation of architectural solutions which do not meet the current European Green Deal requirements. Due to the energy crisis, such architectural solutions are also expensive to manage. The wish to rehabilitate the above-mentioned stock stimulates the adoption of new instruments, such as energy communities and participatory energy management models. These instruments achieve a sustainable energy set-up and drive both social and economic development.

A significant portion of postwar buildings, typically concentrated in suburban areas, are now difficult assets to manage due to their poor sustainability and limited replacement feasibilities. This paper focuses on strategies to improve their metabolism using energy-saving measures based on optimizing energy needs and integrating internal and external energy sources: a new organizational model for energy management should focus first on saving energy, and then on the possibility of integration into a local energy network. This positively affects the anthropogenic impact and becomes a role model for aggregating buildings not only into a district system, but also into a wider, large-scale energy network. The paper shows a significant case study of actual retrofitting intervention that is examined in order to confirm the theoretical guidelines proposed in the first part of the paper. Moreover, another significant case study, taken from common practice, is illustrated, in which different levels of retrofitting are tested. While taking into account the complexity and fragmentation of private property both in a single building and in the city, some strategies are finally described with the aim of reducing the anthropic impact of the postwar building stock.