The project involved a series of energy efficiency interventions aimed at reducing the building’s operating costs, lowering primary energy consumption and consequently reducing its environmental footprint and CO₂ emissions. At the same time, the interventions were designed to achieve thermal comfort for the building’s occupants, as well as improved visual comfort. More specifically, all external window and door frames were replaced with new, energy-efficient units, while the building envelope was thermally insulated using a composite external thermal insulation system, applied to the masonry walls and ceilings/roof elements. In parallel, interventions were carried out on the building’s heating systems, including the use of more efficient heating systems and fuels, the thermal insulation of distribution pipework, and the installation of heating control and automation systems. Furthermore, higher-efficiency lighting systems were installed, while simultaneously improving the visual comfort of the building’s occupants. Renewable energy interventions were also incorporated, including the installation of a photovoltaic system for net metering of the electricity consumed by the building. As a result of these interventions, the building’s energy performance has been significantly improved, and it is now classified in Energy Performance Category “A”.