*3.1. Boundary Conditions*

The school year begins in mid-September. This study was developed one month after the beginning of classes, with the autumn just begun. Autumn 2019 presented itself as a time of slightly higher temperatures than usual. The average temperature of this season tends to be around 20 ◦C, but

in this case, it has been recorded at an average of 1 ◦C more. No rainfall was recorded in the days leading up to the survey.

On the day of the survey, the outdoor temperature variation exceeded 15 ◦C. In the morning at the beginning of classes, 18 ◦C was measured and at the exit, 34 ◦C was reached. This difference has a great influence on the variation in the thermal sensation of the students throughout the morning (Figure 3).

**Figure 3.** Outdoor temperature evolution in Seville during the study period.

Figure 4 shows a slight deviation from the CS1 and CS2 class towards heat sensations with respect to the CS3 class, who were more comfortable thermally because their class schedule was 10 to 11 hours and the average temperature measured was 26.2 ◦C. Meanwhile, for the CS1 and CS2 groups, the time frame in which they did the questionnaires and the discussion was 11:30–12:30 and 12:30–13:30, respectively, and the average temperature measured was 27.4 ◦C.

**Figure 4.** Thermal sensation reported by students.

Despite this, when assessing overall comfort (Figure 4), CS1 gets a rating somewhat worse than CS3. This is indicative that there are factors that are affecting comfort beyond temperature.

Figure 5 shows the comfort sensation reported by students. The valuations were affected by several overall comfort parameters, as well as the schedules and time-frames for the assessments, resulting in different distribution of rating among CS1, CS2 and CS3.

**Figure 5.** Comfort sensation reported by students.

Another value that can influence the results is the clothing of the occupants, as it has been evaluated and established that the conditions in this aspect are very similar, since the variation is minimal (Figure 6).

**Figure 6.** Clothing index (clo) in the classrooms.
