## 4 Conclusions  
The primary goal of this paper was to investigate the existing residential building stock in MED countries or regions represented by the HAPPEN project consortium, in order to assess key data concerning the general features and total energy consumption of residential buildings, allowing the definition of representative buildings as a basis for cost-benefit analysis. The analysis began with the compilation of the essential information from past European and regional projects, publications, and reviews of related literature on the topic, \begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline \multicolumn{1}{c}{**No. of RB**} & \multicolumn{8}{c}{**Representative Buildings in Each Cluster SFH/MFH**} \\ \hline \multirow{3}{*}{\(1\)} & T2C9 & T7C1 & T14C11 & T4C7 & T2C4 & T4C7 & T5C1 & T7C12 & T5C3 \\  & T4C1 & T5C10 & T5C11 & T5C8 & & & & \\
3 & T2C7 & T6C5 & T13C7 & T12C11 & T4C15 & & & \\
4 & T2C1 & T12C1 & T10C1 & T9C14 & & & & \\
5 & T2C3 & T7C1 & T10C6 & T6C5 & T6C9 & T8C7 & T3C9 & T9C7 & \\
6 & T10C7 & T3C1 & T2C1 & & & & & \\
7 & T7C1 & T8C1 & T2C1 & & & & & \\
8 & T9C2 & T11C1 & & & & & & \\
9 & T10C16 & & & & & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 7: Clustering Method 3—RBs in each cluster for a 9-cluster scenario. \begin{table}
\begin{tabular}{c c c} \hline \hline \multicolumn{1}{c}{**More Representative Building**} & **Reference for Table S1** \\ \hline \multirow{3}{*}{\(1\)} & T5C11 & France, MFH, 2000–2010 \\  & T7C1 & Croatia, SFH, 1981–2000 \\  & T8C1 & Italy, MFH, \textless{}1980 \\ T11C1 & Greece, SFH, 1981–2000 \\ \hline \hline \end{tabular}
\end{table} 
Table 10: Representative building of Clustering Method 4 (reference Table S1). \begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline \multicolumn{1}{c}{**No. of RB**} & \multicolumn{8}{c}{**Representative Buildings in Each Cluster SFH/MFH**} \\ \hline \multirow{3}{*}{\(1\)} & T2C9 & T7C1 & T14C11 & T4C7 & T2C4 & T4C7 & T5C1 & T7C12 & T5C3 \\  & T4C1 & T5C10 & T5C11 & T5C8 & & & & \\  & T2C7 & T6C5 & T13C7 & T12C11 & T4C15 & & & & \\ \hline \multirow{3}{*}{\(2\)} & T2C1 & T12C1 & T10C1 & T9C14 & & & & \\  & T2C3 & T7C1 & T10C6 & T6C5 & T6C9 & T8C7 & T3C9 & T9C7 & \\ \hline \multirow{3}{*}{\(3\)} & T10C7 & T3C1 & T2C1 & & & & & & \\  & T7C1 & T8C1 & T2C1 & T9C14 & T1C1 & T9C5 & & & \\ \hline \multirow{3}{*}{\(4\)} & T9C2 & T11C1 & & & & & & & \\  & T10C16 & & & & & & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 8: Clustering Method 4—RBs in each cluster for a 4-cluster scenario. \begin{table}
\begin{tabular}{c c} \hline \hline \multicolumn{1}{c}{**No. of RB**} & \multicolumn{3}{c}{**Representative Buildings in Each Cluster SFH/MFH**} \\ \hline \multirow{3}{*}{\(1\)} & T2C9 & T7C1 & T14C11 & T4C7 & T2C4 & T4C7 & T5C1 & T7C12 & T5C3 \\  & T4C1 & T5C10 & T5C11 & T5C8 & & & \\  & T2C7 & T6C5 & T13C7 & T12C11 & T4C15 & & & \\ \hline \multirow{3}{*}{\(2\)} & T2C1 & T12C1 & T10C1 & T9C14 & & & \\  & T2C3 & T7C1 & T10C6 & T6C5 & T6C9 & T8C7 & T3C9 & T9C7 & \\ \hline \multirow{3}{*}{\(3\)} & T10C7 & T3C1 & T2C1 & & & & & \\  & T7C1 & T8C1 & T2C1 & T9C14 & T1C1 & T9C5 & & \\ \hline \multirow{3}{*}{\(4\)} & T9C2 & T11C1 & & & & & \\  & T10C16 & & & & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 9: Representative building of Clustering Method 3 (reference Table S1). as well as other sources of statistical data or summarized information, in order to obtain a realistic picture of the residential building stock in the specific areas. The gathering of information for each nation participating in the HAPPEN project was structured by using a thorough template that includes precise data essential for the identification of representative structures. Depending on the information available, a real or theoretical building was selected to provide performance data, which would identify the corresponding category. Overall, the study objectives were met by identifying the most significant building classes (in terms of substantial renovation effect) to be further evaluated throughout the duration of the project.