## 3 Results and Discussion
### Life-Cycle Cost Analysis  
The water efficiency design was also carried out and incorporated into the life-cycle cost analysis. The tested buildings were considered in the Lahore region, where the availability of water is not an issue. That is why the cost of water is very low. The savings in the cost due to water was not significant but lead to a gain in LEED points. The water efficiency was applied to the house, office, and the warehouse buildings, and results are reported in Table 10.  
A detailed point-based analysis was conducted for the US-LEED certification on the tested buildings. The water efficiency, energy-efficient design, and site design helped to achieve the certification points. The fee for certification was also calculated and included in the life-cycle cost analysis (LCCA) of the building. The points for an open space design and carbon offsets were also considered. US LEED gives 18 points for optimizing the energy performance for the building and 5 points for LCCA, which has been carried out for the buildings. The expected results for the certification are reported in Table 11.  
For the life-cycle cost analysis, the base model and the final configured model were utilized. Windows that pointed towards the sun and caused direct exposure was replaced with optimized wall, window, and roof materials. Table 12 shows the used optimized combinations for LCCA.  
\begin{table}
\begin{tabular}{c c} \hline
**Buildings** & **Water Saved (\%)** \\ \hline House & 12 \\ Office & 21 \\ Warehouse & 6 \\ \hline \end{tabular}
\end{table}
Table 10: Water savings for the tested buildings.  
Figure 19: Effect of building orientation in energy use. (**a**) House; (**b**) Office; (**c**) Warehouse.  
The simple payback time (_SPBT_) and return on investment (_ROI_) was calculated using the following equations (Equations (1) and (2)), and the results are reported in Table 13.  
\[SPBT=\frac{\textit{Invested to be recovered}}{\textit{Annual recovery}} \tag{1}\]  
\[ROI=\frac{\textit{Annual savings}}{\textit{Invesment to be recovered}}\times 100 \tag{2}\]  
It should be noted that the client has to monitor and share the data for energy consumption for next 5 years with US-LEED to continue the certification. Based on LCCA, the cost recovery period for the tested house building was estimated to 54 years, for the office building it was 13 years, and it was 14 years for the tested warehouse building, including the running and maintenance costs. If the LEED certification is considered, an extra cost needs to be added, which makes it longer for structures to recover the cost. The US-LEED certification cost is almost 1.5% of the estimated house cost, 1% of the office cost, and 0.8% of the total warehouse cost. This percentage is very high as compared to the United States, where construction is more expensive due to very high labor costs.  
It can be seen that around 54 years was required for the tested house building to recover the initial cost. This was due to the fact that the main energy costs for house building were attributed to the night energy usage in summers and winters. The office and warehouse buildings take advantage of a fast cost recovery because the main usage for them is daytime usage, which can be recovered through solar panels. Although there are advantages to the house investment which cannot be denied, due to the very slow recovery costs, they do not seem very feasible. Therefore, in developing countries, the US-LEED certification is recommended for office and warehouse and other large-scale buildings.