## 4 Results and Discussion
Despite this, the analysis conducted in this study was not solely focused on the energy performance of the educational building. It also aimed to evaluate the level of thermal comfort achieved. This was particularly relevant given the building's typical summer operation, during which air conditioning is not used. This operational aspect may limit the payback periods for such improvements, as there are no cooling-related energy expenses. Therefore, the analysis was carried out during the summer months, considering both nighttime periods (residential use by teaching staff) and daytime periods (educational use). The results of the thermal comfort analysis are summarized in Tables 4 and 5. Figure 8: Total energy demand achieved with Case 3 (window replacement and insulation of facades and roofs). Regarding daytime hours, the effectiveness of the measures is evident across all the analyzed combinations. Even in buildings without any insulation improvements, values exceeding 80% were achieved by the end of the century. This advantage largely stems from the extended thermal comfort limits defined by the adaptive model in EN 16798-1:2019. The category used in this study is the most restrictive (category I), yet upper limits of up to 30.7 \({}^{\circ}\)C are accepted. In most cases, the operative temperature remained below this threshold, with no instance of \(t_{pma(out)}\) exceeding 30 \({}^{\circ}\)C. Adopting envelope improvements achieves 100% thermal comfort hours across all the considered scenarios. Although this is a clear advantage, these results do not account for the impact of high indoor temperatures during summer on children's cognitive performance. Elevated temperatures, even when within the thermal comfort range, could still affect children's intellectual performance. In such cases, air conditioning systems may be necessary, as most of the hourly temperature values exceeded 26 \({}^{\circ}\)C.  
Regarding nighttime thermal comfort, Table 5 shows that in 2024, the case study achieved 70% of the nighttime hours as falling within the thermal comfort range. This situation changes drastically in the future scenario. Percentages drop to between 15.81% and 17.10% by 2050, and further decline to between 7.58% and 0.97% by 2080. By the end of the century, nearly all nighttime hours fall outside the thermal comfort range. Envelope improvement strategies do not significantly improve nighttime thermal comfort. In fact, both Case 1 and Case 2 worsen nighttime thermal comfort conditions due to a slight temperature increase, likely caused by the overheating of indoor spaces. In contrast, only Case 3, with roof insulation, improves nighttime comfort. This result is likely explained by the sleeping area being located on the top floor. Slight improvements in nighttime thermal comfort during summer can be achieved. However, an in-depth analysis is required to precisely determine the optimal configuration of envelope improvements, as these measures may lead to overheating, which would negatively impact nighttime comfort. Future projections indicate a negative trend in nighttime comfort hours, necessitating the use of active systems to ensure suitable conditions for restful sleep. This issue is significant in the scientific literature, as no prior studies have directly explored how climate change impacts nighttime thermal comfort conditions. The limited studies available on this topic primarily focus on urban-scale analyses [55] or the operational patterns of mechanical systems [56]. Based on these findings, envelope improvement strategies alone are not an ideal solution for this challenge, especially given the climatic changes projected for the end of the century. They should also promote feasible,