## 5 Results and Discussion
### Comparison between U and U\({}_{\mathit{eff}}\)
\begin{table}
\begin{tabular}{l c c c c c c c c} \hline \hline
**Building Element** & \begin{tabular}{c} **Steel Stud** \\ **Spacing** \\ **[cm]** \\ \end{tabular} & \begin{tabular}{c} \(U_{\mathit{eff}}\) \\ **[W/(m2 K)]** \\ \end{tabular} & \begin{tabular}{c} \(R_{\mathit{eff}}\) \\ **[m2 K/W]** \\ \end{tabular} & \begin{tabular}{c} \(U\) \\ **[W/(m2 K)]** \\ \end{tabular} & \begin{tabular}{c} \(R\) \\ **[m2 K/W]** \\ \end{tabular} & \begin{tabular}{c} \(\Delta U\) \\ **[\%]** \\ \end{tabular} & \
\begin{tabular}{c} \(\overline{\tau}\) \\ **[W/(m K)]** \\ \end{tabular} &
\begin{tabular}{c} \(f_{\mathit{Rsi}}\) \\ **[–]** \\ \end{tabular} \\ \hline Wall & 60 & 0.14890 & 6.71592 & 0.116 & 8.62069 & 28.40 & 0.033 & 0.975 \\ \hline Wall & 30 & 0.16429 & 6.08680 & 0.116 & 8.62069 & 41.60 & 0.048 & 0.975 \\ \hline Roof & 48 & 0.14467 & 6.91228 & 0.110 & 9.09091 & 31.50 & 0.035 & 0.984 \\ \hline Floor & 38 & 0.16534 & 6.04814 & 0.125 & 8 & 32.30 & 0.040 & 0.959 \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Results of the numerical models for the effective thermal transmittance calculation. Figure 9: Model, temperature distribution, and heat flux. thicknesses [23], and about 22% in [45]. On the other hand, in the study conducted by [PERSON] et al. [16], these differences range from 38.83% to 53.67%, which is higher than the differences reported in Table 5. This can be attributed to the low thickness (22 mm) of the continuous external thermal insulation layer which [PERSON] et al. [16] applied to their walls. The same authors [16] studied the effect of steel studs on the thermal transmittance of the flat roof and the ground floor above the crawl space, which resulted in significantly increased \(U_{\textit{eff}}\)-values (\(\Delta U=100.80\%\) for the roof and \(\Delta U=63.23\%\) for the floor). A comparison with the corresponding values from Table 5 shows that these differences are much smaller in the case of the MUZA due to the different design approach (\(\Delta U=31.50\%\) for the roof and 32.30% for the floor, respectively). In the case of the MUZA, the overall thermal performance of the hybrid floor is improved by the external polystyrene insulation layer, whose thickness is double that of [16], while the overall thermal performance of the roof is improved by the installation of a thick continuous internal thermal insulation and by the elimination of the air cavity between the steel studs. Consequently, the linear thermal transmittance \(\psi\) of the considered MUZA's components, as well as the condensation risk (reflected in the temperature factor\(f_{\textit{Rsi}}\)), are also significantly lower. Apart from the linear thermal bridges caused by the steel studs within the building elements, an additional type of thermal bridges can be recognised in LSF structure of the MUZA (namely external walls), which are point thermal bridges, usually driven by mechanical fixations (e.g., fixation of the mineral wool to the OSB as well as the substructure of the ventilated facade). In the case of the MUZA, the fixation of the mineral wool to the OSB sheeting is done using plastic fixings, and, as per EN ISO 6946 [34], can be ignored if thermal conductivity of the fastener is less than 1 W/(m K). Vertilated facade substructure is constructed using Crossfix consoles containing a plastic thermal break [46] with the calculated point thermal bridge coefficient \(\chi=0.0098\) W/K and the \(\Delta U=0.0086\) W/m\({}^{2}\cdot\)K for the reference facade [47]. In addition to the plastic thermal break, the facade substructure consoles were screwed to the steel studs over the OSB sheeting, thus, additionally reducing the impact of the point thermal bridge. Consequently, it was concluded that the aforementioned point thermal bridges will be neglected in this research and will be analysed elsewhere.