Sustainable Construction, LEED as a Green Rating System and the Importance of Moving to NZEB

In this study, in order to evaluate the possibility of achieving the Net Zero Energy Building (NZEB) goal, the history of sustainable construction, and available green-rating systems with specific focus on Leadership in Energy & Environmental Design (LEED) rating system were explained. LEED rating system was selected as the most prevalent rating system in the industry to evaluate and analyze its efficiencies/drawbacks specifically in regards to the energy efficiency. The goal of this study is to answer an important question of the reasons to focus on NZEB concept when LEED rating has come up with a detailed certification process, which is somehow beneficial in regards to energy reduction. NZEB concept is defined as an evolution of very energy-efficient approach and it requires that the buildings have zero energy balance on an annual basis. This paper explains this questions in detail and it consists of three parts: in the first part sustainable building rating system including LEED certification is explained. The second part explains the deficiencies of LEED rating system in regards to the energy performance of buildings and the last part explains the NZEB concept and the movement towards the NZEB target.