By applying the proposed pattern based on optimal physical features of a building, the total amount of energy consumption in a year in Sample B was reduced to 91.5 KWH. Such a reduction shows the direct effect of optimal physical condition on thermal performance of buildings. Subsequently, indicating the size of openings in a building is of considerable importance; these openings can be a means for both receiving and wasting energy. Therefore, the specification of the total area of windows (regarding the type of the examined climate, it is effective as a main index) gains substantial significance. The optimal percentages of openings based on length-to-width ratio in Ilam City’s climate are listed in Table 9, with regards to the proposed optimal pattern.
Table 9.: The extent of the transparency of openings and the building plan’s length-to-width ratio in Ilam City’s climate (%).