Investigating the effective factors on the reduction of energy consumption in residential buildings with green roofs

Heating and cooling of residential and commercial buildings account for approximately 40 percent of world's total energy consumption [1]. This considerable amount of energy consumption have made scientist to search for every possible way to reduce it. Among the most effective approaches is the use of green roof for buildings. Although the positive effects of using such roofs are well proven, the amount of energy reduction which can be achieved by this method is another issue that this paper is trying to investigate. In this study, three different climates of Iran are chosen for the analysis. The results demonstrate that using green roof in Very Hot Dry (Bandar Abbas), Warm Dry (Isfahan), and Mixed Dry (Tabriz) climates causes energy consumption to decrease by approximately 8.5, 9.2 and 6.6 percent, respectively. Considering the reduction of energy consumption as the only desirable benefit of green roof, the payback period would be 25-57 years (depending on the climate).