## 4 Conclusions  
The research presented includes a representative part of currently existing recycled materials, as well as their most representative applications. Similarly, the thermal conductivity coefficient of several samples of cement and expanded clay with extruded polystyrene waste (XPS) has been experimentally determined (0.04 w/mK). These recycled materials can be an interesting alternative if they are used as thermal insulating materials in buildings, allowing thermal conductivity coefficients of up to 0.04 w/mK to be obtained. Furthermore, this work shows the characteristics and energy balances in a representative building of the Spanish construction model in different climatic zones. The Spanish construction code promotes that energy gains/losses occur mainly due to air renewals (\(\approx\)80%) of buildings, with the remaining \(\approx\) 20% due to heat transfer through the envelope. Energy losses occur mainly through the glazing (36%) while in the roof and facade walls (21% and 30%, respectively) the impact is more moderate, dropping considerably in the ground (13%). These values show that some elements of the construction (walls, roof) of the building in which recycled materials can be implemented have a high potential for energy savings. Regarding the energy evaluation of several construction solutions using recycled materials with CDW, as well as the comparison with traditional solutions, the following conclusions can be drawn:  
* Energy savings can range from 8% in warm climates (e.g., Sevilla) to 13% in colder climates (e.g., Soria), being greater in heating than in cooling;
* Incorporating recycled materials into the roof presents greater energy savings potential (up to 7%) than when placed in the facade; \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline  & \multirow{2}{*}{**Heat Transfer**} & \multicolumn{2}{c}{**Heating**} & \multicolumn{2}{c}{**Cooling**} & \multicolumn{2}{c}{**Heating + Cooling**} \\ \cline{3-8}  & & **Cosmumption** & \multirow{2}{*}{**Savings**} & \multicolumn{2}{c}{**Consumption**} & \multirow{2}{*}{**Savings**} & \multicolumn{2}{c}{**Consumption**} \\  & & **(kWh)** & & & **(kWh)** & & **(kWh)** & **Percentage** \\ \hline \multicolumn{8}{c}{SEVILA} \\ \hline Case 1 & Renovations & 64,328 & & 26,291 & & 90,619 & \\ Case 2 & Renovations & 63,825 & 1\% & 26,709 & \(-\)2\% & 90,534 & 0\% \\ Case 3 & Renovations & 62,671 & 3\% & 26,338 & 0\% & 89,009 & 2\% \\ Case 4 & Renovations & 61,999 & 4\% & 26,696 & \(-\)2\% & 88,695 & 2\% \\ Case 1 & Envelope & 17,076 & & 6979 & & 24,054 & \\ Case 2 & Envelope & 16,936 & 1\% & 7087 & \(-\)2\% & 24,023 & 0\% \\ Case 3 & Envelope & 15,819 & 7\% & 6648 & 5\% & 22,467 & 7\% \\ Case 4 & Envelope & 15,523 & 9\% & 6684 & 4\% & 22,207 & 8\% \\ \hline \multicolumn{8}{c}{SORIA} \\ \hline Case 1 & Renovations & 245,576 & & 3189 & & 248,765 & \\ Case 2 & Renovations & 244,595 & 0\% & 3533 & \(-\)11\% & 248,127 & 0\% \\ Case 3 & Renovations & 242,994 & 1\% & 3460 & \(-\)8\% & 245,606 & 1\% \\ Case 4 & Renovations & 241,768 & 2\% & 3838 & \(-\)20\% & 245,606 & 1\% \\ Case 1 & Envelope & 52,772 & & 685 & & 53,457 & \\ Case 2 & Envelope & 51,211 & 3\% & 740 & \(-\)8\% & 51,951 & 3\% \\ Case 3 & Envelope & 47,659 & 10\% & 679 & 1\% & 48,337 & 10\% \\ Case 4 & Envelope & 45,572 & 14\% & 723 & \(-\)6\% & 46,295 & 13\% \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Energy consumption of the building due to the heat transfer of air renewals and through the envelope of the building located in Seville and Soria. * Economic savings due to the reduction in the energy consumption of the cooling system can reach up to 14% for heating in colder climates (e.g., Soria) or 4% for cooling in warm climates (e.g., Seville). The incorporation of recycled materials in various building construction elements has proven to be a success, as it reduces the consumption of raw materials and the energy consumption of the building.