This is an energy and plant requalification intervention of a multi-storey building located in the countryside. The building, built in the 80s with obsolete construction techniques, has been brought back to a state of plant and energy efficiency, through a systematic set of interventions that has allowed the individual housing units to be made independent and functional, requalifying the entire envelope and installing new electric air conditioning systems that, connected to the new photovoltaic systems, obtain properties in energy class 3A.