Energy consumption in public buildings increased drastically over the last decade. Significant policy actions towards the promotion of energy efficiency in the building sector have been developed involving sustainable low-CO2-emission technologies. This paper presents the results of an economic–environmental valuation of a standard energy retrofit project for a public building in a Mediterranean area, integrating a life-cycle assessment (LCA) into the traditional economic–financial evaluation pattern. The study results show that simple retrofit of sustainable low-CO2-emission strategies such as wooden double-glazed windows, organic external wall insulation systems, and green roofs can reduce energy needs for heating and cooling by 58.5% and 33.4%, respectively. Furthermore, the implementation of an LCA highlights that the use of sustainable materials reduces the building’s carbon footprint index by 54.1% after retrofit compared to standard materials, thus providing an additional increase in the socio-environmental–economic–financial results of 18%. Some proposals are made about the accounting of the replacement costs and the residual value as requested in the logic of life-cycle cost (that is the economic extension of the LCA), namely concerning the method to take into account the replacement costs and the residual value. The economic calculation highlights the fundamental role played by tax benefits supporting the building energy retrofit, also in temperate climate zones, thus allowing the creation of environmental benefits in addition to remarkable cost savings.
The application of housing land-use patterns to achieve low CO2 emission in Medan City