Regarding the thermal quality of architectural envelopes, the parameter used is the index of energy performance for envelope (Epi env) calculated through UNI-TS 11300 standards [10]. Epi env is the annual energy requirements necessary to maintain interior spaces at a constant temperature of 20 ◦C, without considering the losses due to the thermal plant. Epi env reported in Fig. 5 show a slight variation between historical and modern buildings. However no value cannot be considered acceptable having an average value of 18 kWh/m3 per year, as far as the prescribed standard values of about 10-12 kWh/m3 per year [12]. Thermal plants performances shown in Fig. 6 are more similar between historic and modern buildings. The parameter used is the global seasonal efficiency ( g)