Energy efficiency and preservation of diffuse historic buildings: opportunities and open questions

The aim is to address the issue of architectural heritage belonging to the diffuse residential buildings, most of which are privately owned and used as residences, to the possibility of being subjected to energy retrofitting, a highly topical issue, while at the same time maintaining their historic features and aesthetic prerogatives. If the historical-constructive characteristics of the constructions of the residential buildings are taken into account, it emerges that they are the result of a centuries-old relationship between the environment in which they were conceived and been renovated over centuries and the resources offered by the territory itself. For essentially utilitarian reasons, they have defined peculiarities that do nothing more than support and enhance the place where they were built. The extensive use of wood, the oversized structures, the orientation of the buildings and their closeness, when they are located in urban centres, give widespread historic buildings specific features similar to those required today for the proper management of buildings from an energy point of view. The energy retrofitting projects should therefore be mainly linked to the air conditioning systems, which, with greater efficiency and less invasiveness, can increase the thermal comfort inside the individual building units, which in principle could be exempt from interventions that involve invasiveness in terms, above all, of aesthetics. In this regard, some examples of energy retrofit on historical residential buildings halfway between the farmhouse and the Lombardy courtyard will be analysed. At this juncture, the diagnostic analyses, mainly non-destructive and usually used in the field of restoration, can provide a valid and fundamental contribution both for the identification of thermal bridges in buildings, and to provide data for an effective dimensioning of the characteristics of the system and its placement within the building units, without any disruptions and maximising the qualities linked to their conformation and structure. In conclusion, a discussion is made that attempts to combine respect for the historical characteristics of a building with energy efficiency work, trying to make it more durable and more environmentally sustainable, but also trying to meet the legitimate aspirations of the property.