## 3 Results and Discussion  
### Thermal Conditions  
Indoor and outdoor levels of T and RH were recorded for the entire experimental period in order to assess the thermal comfort conditions within the museum during warm and cold months. Thermal conditions within each room tended to fluctuate depending on the floor, the use of HVAC systems, and the time of year. Table 1 depicts the mean monthly results of the T and RH levels monitored in and out of the building and were divided per floor. From this Table, one may notice that the highest mean monthly value of T was found on the second floor, reaching 31.95 \({}^{\circ}\)C in August 2020 (with ambient T of 30.96 \({}^{\circ}\)C), while the maximum T within the building (34.6 \({}^{\circ}\)C) was recorded on the same floor during the same month, with maximum outdoor T reaching 39.29 \({}^{\circ}\)C. The lowest mean value of T was recorded on the ground floor during January 2020 (14.67 \({}^{\circ}\)C), with an outdoor T of 10.37 \({}^{\circ}\)C, while amid the same month, the minimum value (9.56 \({}^{\circ}\)C) was found on the first floor (specifically in the Entrance), with the lowest ambient value reaching 6.67 \({}^{\circ}\)C. It is clear that during the hot summer months, the rooms on the second floor are the most vulnerable to elevated T levels, as they are directly exposed to large amounts of solar radiation due to the Earth's angle during this season. The building absorbs thermal energy from the sun and gradually yields it within as time passes. Thus, the preservation of the exhibits in the Philosophy and Applied Sciences rooms should be taken under careful consideration, especially during the warmer days of the year. On the contrary, the lowest average T levels were monitored on the ground floor, during the colder months, which was mainly because no HVAC system operates in the Auditorium if it is occupied by visitors. As expected, the rooms on the first floor retain intermediate levels of T, which is mainly due to the operation of air conditioners as well as to the extra thermal insulation from the ground and the second floor. Nevertheless, as mentioned above, the lowest T value was recorded in the Entrance, which was mainly due the frequent opening of the door. Referring to RH, the highest monthly average value was recorded on the third floor (64.44%) during November 2019, a month with frequent episodes of precipitation in the city of Athens, when the mean external RH was 69.83%. However, this is only an exception, as the regular trend of RH is to be elevated mainly on the ground floor for almost all of the experimental months. The non-frequent use of HVAC in this space does not favor dehumidification processes, and thus, elevated levels of RH appear. Figures 4 and 5 summarize the results of internal and external T and RH for all of the investigated rooms during the entire experimental period. In both Figures, the coloured dotted lines represent the proposed limit ranges needed to achieve the desired thermal comfort conditions for the inhabitants, which were first reported in the research of [PERSON] et al. (2016) and the National Building Regulations (2017). It should be noted that the proposed  
Figure 3: Air quality sensor situated within the building. T limits refer to the cold (from October to April, 20-23 \({}^{\circ}\)C) and warm periods (from May to September, 23-26 \({}^{\circ}\)C) of the year, while the limit range of RH (30-60%) is annual.