## 4 Results
### Comfort Conditions Analysis
#### 4.1.1 Monitoring for Selected Winter Days
As shown in Figure 3, the calculated values of PMV and PPD for typical working hours in a public office were outside the comfort range with a percentage of dissatisfied people from 12% to 24%. The calculation was done considering the measurements of air speed during the selected day. With fan-coils turned on, the operative temperature varied between 19.3 \({}^{\circ}\)C and 21.7 \({}^{\circ}\)C with an average daily value of 20.7 \({}^{\circ}\)C; thus, it was included in the comfort zone. The relative humidity varied between 36% and 40%, with an average daily value of 40%. According to Figure 4, the value of the predicted mean vote was always near the lower limit, but the percentage of dissatisfied people was under 10% starting from the early afternoon. Figure 5 indicates the major attitude of the radiant system to maintain more stationary conditions. The neutral point was very close during the late morning and afternoon; instead, starting from 20:00, the PMV values tended to \(-\)0.5 also if the temperature was near 21 \({}^{\circ}\)C with a low level of relative humidity (35-37%). In this case, the operative temperature was varied between 20.4 \({}^{\circ}\)C and 22.5 \({}^{\circ}\)C, and the average daily value was 21.1 \({}^{\circ}\)C, while the average daily relative humidity was 39%. It has to be underlined that the floor heating usually has different comfort effects on the human body when compared to convective systems, because it has stronger effects on lower body parts, while the fan coil unit creates a layer of conditioned air around the body. Therefore, it would be not accurate to compare the two systems and their effect on  
Figure 4: PMV and PPD calculation: fan coil units. Figure 3: PMV and PPD calculation: baseboards. the comfort level based on the operative temperature. However, the measured value of floor surface temperature suggests that for the available test-room, the radiant asymmetry is always under the threshold value. For example, the widely used \(\Delta\text{t}_{\text{pr}}\) represents the asymmetry of a radiant field by referring to the difference between the plane radiant temperature of the two opposite sides of a small plane element [45], typically 0.6 m above the floor. Additionally, if this measure is not available, the measures at 0.1 m and 1.1 m that are shown in the next section indicate that there is not vertical and horizontal asymmetry for the designed system. Moreover, the current floor surface temperature requirement (T\({}_{\text{f}}\) in Table 2) based on the comfortable contacting temperature is always respected. Indeed, it is believed that an excessively hot floor will lead to local thermal discomfort complaints [46]. However, further investigations will be done for evaluating different time exposures, the asymmetric-satisfaction requirement. Finally, it can be concluded that only the fan-coil units and the radiant floor system are able to assure comfort conditions if the air temperature is also frequently higher than 20 \({}^{\circ}\)C, which corresponds to the set point value. The low value of relative humidity influences, in all analyzed cases, the calculated comfort indexes.