## 4 Results
### Comfort Conditions Analysis
#### 4.1.1 Monitoring for Selected Winter Days  
Firstly, a daily comparison was made considering comparable external climatic conditions. The selected days were 1 January with baseboards, 1 February with fan-coil units, and 7 th February for floor radiant panels. Table 4 shows the main parameters useful to describe the monitored external conditions. Figure 2 reports the trends of the outdoor (T\({}_{\text{ex}}\)) and indoor air temperature (T\({}_{\text{a\_c}}\)) and the mean radiant temperature (T\({}_{\text{r}}\)) recorded by the sensors in the center of the room. \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline  & \multicolumn{3}{c}{**1 January**} & \multicolumn{3}{c}{**1 February**} & \multicolumn{3}{c}{**7 February**} \\ \hline  & Max & Min & Mean & Max & Min & Mean & Max & Min & Mean \\ Temperature (\({}^{\circ}\)C) & 14.8 & 5.1 & 9.8 & 14.5 & 5.7 & 9.9 & 14.5 & 4.1 & 8.5 \\ Global solar radiation (W/m\({}^{2}\)) & 602 & 12 & 220 & 583 & 10 & 218 & 750 & 25 & 208 \\ Relative humidity (\%) & 100 & 59 & 79.2 & 100 & 58 & 81,5 & 99 & 49 & 80.5 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Climatic data for reference days. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Measure** & **Sensor** & **Range** & **Accuracy** & **Response Time** \\ \hline
**Temperature** & PT-100 NESA & \(-40\div 80\)\({}^{\circ}\)C & 0.015\({}^{\circ}\)C & \(<\)60 s \\
**Relative humidity** & PT-100 NESA & \(0\div 100\%\) & 0.1\({}^{\circ}\)C & \(<\)60 s \\
**Temperature** & PT-100 TESTO & \(-20\div 70\)\({}^{\circ}\)C & 0.1\({}^{\circ}\)C & \(<\)60 s \\
**Relative humidity** & PT-100 TESTO & \(0\div 100\%\) & 0.1\({}^{\circ}\)C & \(<\)60 s \\
**Surface temperature** & Thin-flowmeter & \(\geq\)205\({}^{\circ}\)C & \(\pm\)0.8\({}^{\circ}\)C & 0.20 s \\
**Air speed** & Anemometer & 0.1–30 m/s & 0.1 m/s & \(<\)60 s \\
**Mean radiant temperature** & Globe thermometer & \(-40\div +60\)\({}^{\circ}\)C & 0.01\({}^{\circ}\)C & \(<\)10 s \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Technical specifications of the inner sensors. With the radiant floor and the baseboard system, the two profiles were almost stackable. In case of baseboards, since these were mounted near the walls, the radiative heat exchange increased and thus T\({}_{\rm r}\) was close to the indoor air with an average daily difference of 0.01 \({}^{\circ}\)C and a maximum difference of 0.25 \({}^{\circ}\)C at 7:10. When the radiant floor was considered, an average daily difference of 0.31 \({}^{\circ}\)C was recorded, while the maximum difference was 0.82 \({}^{\circ}\)C; it occurred during the late afternoon. On the other hand, the radiant temperature was higher (maximum deviation of 0.67 \({}^{\circ}\)C) than T\({}_{\rm a\_c}\) during the early afternoon when the combined effect of the solar radiation and floor temperature contributed to heat the building envelope. Additionally, in this case the monitored trend allowed us to highlight the different operating principle of the compared systems. The values of surface temperatures recorded on the floor also suggested uniform conditions when the radiative heat exchange was considered. Figure 2: Record temperatures in the center of room: **(a)** baseboards; **(b)** fan-coil units; **(c)** radiant heating floor. floor was operating. More in detail, considering the five available sensors, the average daily T\({}_{\text{s,floor}}\) varied between 20 \({}^{\circ}\)C and 21 \({}^{\circ}\)C. The highest value was 22.8 \({}^{\circ}\)C and it was recorded at 12:20 when there was thus an important contribution of solar radiation. This was in agreement with the trend of T\({}_{\text{a,c}}\) and T\({}_{\text{r}}\) proposed in Figure 2c. Considering the calculated value of operative temperature, starting from the measurements of the black globe in the room center, it ranged between 18.6 \({}^{\circ}\)C and 20.1 \({}^{\circ}\)C when the baseboards were active, with an average daily value of 19.6 \({}^{\circ}\)C, which did not match with the comfort requirements. The relative humidity varied between 43% and 53%.