3.4. Results and possible retrofitting solutions
Since the school belongs to historical building heritage built in load-bearing masonry, the audit results confirmed
that this construction type building has good envelope quality. In fact, the envelope performance simulations showed
that in winter there is a temperature difference of about 5°C between inside and outside that increases up to 7°C in
summer. This positive effect is due to the external walls thickness (70 cm) that causes a thermal lag of 9.3 h and in
few words a better energy performance in comparison with different building construction types (concrete
constructions). The data, collected through the questionnaires filled by students, showed that the thermal comfort
perceptions were ok for 64%, slightly warm for 21% and slightly cool for 14%, during winter even if in some days
they feel slightly warm/warm but anyway they cannot operate in reducing indoor temperature for the thermostatic
valves lack on the radiators. However, the lowest comfort levels are recorded near the thermal bridges under the
windows due to the reduction of the wall thickness (30 cm). The uninsulated flat roof has the waterproofing system in
bad maintenance conditions that cause water seepage problems into the classrooms. Another peculiarity of this
construction type is that it does not allow a horizontal continuous series of windows and thus the amount of lighting
is not homogeneous even if the considerable height of the windows allows the entrance of the light more in depth.
These results were obtained by RELUX simulations, instrumental measurements on site and students’ perceptions [7]
(Fig.3). Moreover, the artificial lighting system is not sufficient according to the lighting standards (UNI EN 12464-
1) also integrated with the natural light in the days with bad weather conditions.
The green info hotspots include the different retrofitting intervention alternatives according to cost levels (low,
medium and high cost), payback times, and the achievable performance improvements