## Materials and Methods
### Testing Scenarios Considered  
The system shown in Figure 2b was placed on a user's belt, in line with the \"abdomen level\" indicated in the ISO 7726 [35], corresponding to a height of approximately 0.6 m when sitting and 1.1 m when standing, on two different days: 8 and 14 November 2022, considering two scenarios:  
* Autumn, with an air temperature in the range of 21 \({}^{\circ}\)C, a thermal resistance of clothing of 1.0 clo, a real office scenario with a user who could move freely out of the office (8 November 2022)  
Figure 2: Hardware used for the test: (**a**) design of 3D-printed parts; (**b**) the ten iButtons DS1923 as mounted on 3D-printed parts with carbon rod. * Summer, with an air temperature in the range of 28 \({}^{\circ}\)C, a thermal resistance of clothing of 0.5 clo, an office scenario reproduced in the ZEBlab [41] with a user enclosed in an indoor space (14 November 2022) Figure 3 shows the two experimental setups with the environments considered, the user position, and the hardware worn with a detail of the developed system as fitted by the user. Figure 3: Autumn and summer setup: (**a**) office plant used for the autumn scenario; (**b**) ZEBlab room used for simulating the summer scenario (HE = Heat Exchanger; EHwF = Electric Heater with Fan; with blue dot, the position of Pt100 connected to the thermoregulatory used to control the EHwF); (**c**) picture of the autumn scenario with user and hardware in the considered environment; (**d**) detail of the hardware as mounted in the autumn scenario; (**e**) picture of the summer scenario with user and hardware in the considered environment; (**f**) detail of the hardware as mounted in the summer scenario. In the autumn scenario, heating was provided by one radiator placed under the window (Figure 3a). In the summer scenario, the highest temperature of approximately 28 \({}^{\circ}\)C was achieved by using an electric heater with fan (Figure 3b). It was controlled by a thermoregulatory, the Verner HT NiPT-1, which guarantees a temperature setpoint of 28 \({}^{\circ}\)C (\(\pm\)0.5). The thermoregulatory was connected to a platinum resistance Pt100 positioned near the right wall of the room (blue dot in Figure 3b) that could provide the air temperature. In the autumn scenario, ventilation was provided by the manually opening of doors and windows. In the simulated summer scenario in the ZEBlab, ventilation was provided by mechanical ventilation with two heat recovery units that allowed a complete air exchange per hour. In both scenarios, the rooms were occupied by the tester alone wearing an Empatica E4 wristband on the left arm. In the autumn scenario, the wearable system composed of the ten iButtons DS1923 sensors was worn on the opposite side of the window glass, although the environment was not characterized by direct sunlight during the day and test hours. In the simulated summer scenario, on the other hand, the wearable system was worn on the window side, as this was characterized by triple glazing with low emissivity and, during the test the position where the user and the ten measurement points were located, was not characterized by direct sunlight. The additional light sources are fluorescent tubes in the case of the autumn scenario and LED in the case of the summer scenario. Even though it was possible to perform Human Activity Recognition (HAR) using semi-supervised techniques [42] (i.e., sitting, walking, etc. ), the participant used the tag button available on the E4 to indicate both the beginning of a walking activity and the end of the single walking activity. In this way, we could identify the period of movement (with a red line in Figure 3) and the period the user was not sitting in the office (gray-filled area in Figure 3) considered for the autumn scenario. The Empatica E4 also provided us with the ability to record skin temperature, which was then correlated with the air temperature measured by the 10 iButtons to check for a possible correlation.