## 6 Conclusions  
This study presents an energy, environmental, and cost analysis studying the reduction in thermal energy demand for residential condomium buildings following the implementation of specific energy measures. This study focuses on 2940 buildings located in Naples, Southern Italy, all equipped with centralized heating systems based on traditional boilers. Seven common building geometries/shapes were studied, identifying the number of buildings for each geometry to generalize the results. The building geometries are defined using the Google SketchUp TRNSYS3d plug-in, and the dynamic energy simulations are performed in the TRNSYS environment. Type 56 of TRNSYS is used to simulate the buildings, and its outputs are considered extremely reliable for dynamic simulations of building and building-plant systems. The results show that the primary energy consumption of the current heating systems totals 809 GWh/year. The energy-saving measures considered--thermal insulation for external walls and the replacement of boilers with condensing systems--were simulated in two adoption scenarios: 25% and 100%. In the full adoption scenario, primary energy savings reach 224 GWh/year (28.0%), and CO2 emissions are reduced by 45 kt/year. The annual economic savings for users is estimated at 2.00 \(\ell\)/m\({}^{2}\), while the payback period aligns with the literature findings. However, without financial incentives, these energy \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline \multicolumn{1}{c}{\multirow{2}{*}{**Thermal Insulation on the External Walls**}} & \multicolumn{3}{c}{**Boiler Replacement**} & \multicolumn{3}{c}{**Yearly Economic Saving and Payback**} \\  & **Io [c]** & **Technical** & **Capital** & **Cipital** & **Loc [c]** & **Io [c]** & **Technical** & **Total Capital** & **Limit** & **\(\Delta\)C** & **SPB** \\  & **Cost [c]** & **Cost [c]** & **Cost [c]** & **Cost [c]** & **Cost [c]** & **Cost [c]** & **[c/y]** & **[y]** \\ \hline A1 & 76,424 & 19,106 & 95,530 & 540,000 & 11,158 & 1674 & 12,831 & 270,000 & 2175 & 49.8 \\ \hline B1 & 229,271 & 57,318 & 286,589 & 2,100,000 & 22,724 & 3409 & 26,133 & 1,050,000 & 13,831 & 22.6 \\ \hline C2 & 205,920 & 51,480 & 257,400 & 1,500,000 & 22,724 & 3409 & 26,133 & 750,000 & 6260 & 45.3 \\ \hline D1 & 124,188 & 31,047 & 155,236 & 1,200,000 & 21,214 & 3182 & 24,396 & 600,000 & 4564 & 39.4 \\ \hline D2 & 128,494 & 32,124 & 160,618 & 1,200,000 & 21,214 & 3182 & 24,396 & 600,000 & 4474 & 41.4 \\ \hline E1 & 133,741 & 33,435 & 167,177 & 1,260,000 & 21,214 & 3182 & 24,396 & 630,000 & 4522 & 42.4 \\ \hline E2 & 138,378 & 34,595 & 172,973 & 1,260,000 & 21,214 & 3182 & 24,396 & 630,000 & 4418 & 44.7 \\ \hline F1 & 85,977 & 21,494 & 107,471 & 480,000 & 11,158 & 1674 & 12,831 & 240,000 & 2207 & 54.5 \\ \hline F2 & 88,957 & 22,239 & 111,197 & 480,000 & 11,158 & 1674 & 12,831 & 240,000 & 2131 & 58.2 \\ \hline G1 & 191,059 & 47,765 & 238,824 & 1,500,000 & 28,564 & 4285 & 32,849 & 750,000 & 6852 & 39.6 \\ \hline G2 & 197,683 & 49,421 & 247,104 & 1,500,000 & 28,564 & 4285 & 32,849 & 750,000 & 7409 & 37.8 \\ \hline \hline \end{tabular}
\end{table} 
Table 11: Economic analysis: economic savings and simple payback for each building geometry. \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline
**Scenario** & **PE\({}_{\text{RS}}\) [GWh/y]** & **PE\({}_{\text{PS}}\) [GWh/y]** & **PES [\%]** & **CO\({}_{\text{2,RS}}\) [kt/y]** & **CO\({}_{\text{2,PS}}\) [kt/y]** & **\(\Delta\)CO\({}_{\text{2}}\) [kt/y]** \\ \hline
25\% & 809 & 753 & 56 & 7 & 162 & 151 & 11 \\
100\% & 809 & 585 & 224 & 28 & 162 & 117 & 45 \\ \hline \hline \end{tabular}
\end{table} 
Table 12: The penetration of the measures for 25% and 100% of the buildings belonging to the Naples municipality. efficiency measures are not economically viable. The Superbonus 110% makes the proposed measures cost-free for users, resulting in significant natural gas cost savings.