## 5 Economic Evaluation
### Changes in Investment Costs Due to Window Changes  
By examining the price change of windows according to the change of the thermal transmittance of the windows, the energy saving effect of investment in passive elements was identified. The window model suitable for the thermal transmittance rate used in this simulation was selected from among the products reported by the Energy Consumption Efficiency Rating System of the Korea Energy Agency. The unit price of the window model was investigated by the Public Procurement Service's Nara Marketplace and the manufacturer's estimate. As a result of the investigation, the thermal transmittance rate and window cost are inversely proportional to the windows and doors of the same manufacturer and the same product family (synthetic resin frame, Misecogi) as shown in Table 10. As shown in Figure 8, there is a high correlation between the cost invested in windows and energy increase.  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline \multicolumn{1}{c}{\multirow{2}{*}{**Simulation Case**}} & \multicolumn{2}{c}{**Window U-Value**} & \multirow{2}{*}{**Manufacturer**} & \multirow{2}{*}{**Cost [KRW]**} \\ \cline{5-5} \multicolumn{1}{c}{} & & \multicolumn{1}{c}{**[W/m\({}^{2}\)K]**} & & & K & 91,770,149 \\ \hline \multirow{5}{*}{
\begin{tabular}{c} Seoul and \\ Incheon \\ \end{tabular} } & A-D & 1.150 & & H & 97,116,420 \\ \cline{2-5}  & & & K & 103,874,126 \\ \cline{2-5}  & B-E & 1.000 & & H & 99,986,733 \\ \cline{2-5}  & C-F & 0.880 & & K & 113,085,940 \\ \cline{2-5}  & G-J & 1.510 & & K & 84,370,083 \\ \cline{2-5}  & H-K & 1.150 & & K & 91,770,149 \\ \cline{2-5}  & H-K & 1.150 & & H & 97,116,420 \\ \cline{2-5}  & I-L & 1.000 & & K & 103,874,126 \\ \cline{2-5}  & & H-L & 99,986,733 \\ \hline \hline \end{tabular}
\end{table}
Table 10: Window product cost by U-value.  
\begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline \multicolumn{1}{c}{\multirow{2}{*}{\begin{tabular}{c} **Simulation** \\ **Case** \\ \end{tabular} }} & \multicolumn{4}{c}{**U-Value [W/m\({}^{2}\)K]**} & \multirow{2}{*}{**Sum of**} \\ \cline{2-5} \multicolumn{1}{c}{} & & \multicolumn{1}{c}{**Adjacent**} & \multicolumn{1}{c}{**Adjacent**} & \multicolumn{1}{c}{**Exterior**} & \multicolumn{1}{c}{**Exterior**} & \multicolumn{1}{c}{**Graund**} \\ \cline{5-5} \multicolumn{1}{c}{} & & \multicolumn{1}{c}{**Coiling**} & \multicolumn{1}{c}{**Wall**} & \multicolumn{1}{c}{**Roof**} & \multicolumn{1}{c}{**Wall**} & \multicolumn{1}{c}{**Floor**} & \multicolumn{1}{c}{**Window**} & \multicolumn{1}{c}{**Energy Demand**} \\ \hline \multirow{5}{*}{\begin{tabular}{c} Seoul \\ \end{tabular} } & A & 0.210 & 0.240 & 0.150 & 0.170 & 0.170 & 1.150 & 85,732 \\ \cline{2-5}  & B & 0.210 & 0.240 & 0.150 & 0.170 & 0.170 & 1.000 & 83,628 \\ \cline{2-5}  & C & 0.210 & 0.240 & 0.150 & 0.170 & 0.170 & 0.880 & 80,565 \\ \hline \multirow{5}{*}{\begin{tabular}{c} Incheon \\ \end{tabular} } & D & 0.210 & 0.240 & 0.150 & 0.170 & 0.170 & 1.150 & 88,317 \\ \cline{2-5}  & E & 0.210 & 0.240 & 0.150 & 0.170 & 0.170 & 1.000 & 85,971 \\ \cline{2-5}  & F & 0.210 & 0.240 & 0.150 & 0.170 & 0.170 & 0.880 & 83,043 \\ \hline \multirow{5}{*}{\
\begin{tabular}{c} Gwangju \\ \end{tabular} } & G & 0.260 & 0.310 & 0.180 & 0.220 & 0.220 & 1.510 & 94,330 \\ \cline{2-5}  & H & 0.260 & 0.310 & 0.180 & 0.220 & 0.220 & 1.150 & 92,943 \\ \cline{2-5}  & I & 0.260 & 0.310 & 0.180 & 0.220 & 0.220 & 1.000 & 91,280 \\ \hline \multirow{5}{*}{
\begin{tabular}{c} Busan \\ \end{tabular} } & J & 0.260 & 0.310 & 0.180 & 0.220 & 0.220 & 1.510 & 82,366 \\ \cline{2-5}  & K & 0.260 & 0.310 & 0.180 & 0.220 & 0.220 & 1.150 & 81,457 \\ \cline{1-1} \cline{2-5}  & L & 0.260 & 0.310 & 0.180 & 0.220 & 0.220 & 1.000 & 80,383 \\ \hline \hline \end{tabular}
\end{table}
Table 9: Energy demand according to the thermal properties of windows and doors.