Sustainable design rating systems for buildings emerged in the early 1990s globally as an essential method for improving building performance by focusing on conserving energy and minimizing environmental impact. Due to the complexity of buildings, different sustainable-building rating system definitions, as well as the varied target markets and implementation processes, it is difficult to fairly compare different rating systems. The lack of clear knowledge about the comparati

Primary energy is the energy that is found directly from nature prior to human induced extraction or transformation. It is a commonly accepted metric for measuring building energy efficiency. The main sources of primary energy include oil, coal/peat/shale, natural gas, hydro, nuclear, and others. These sources are converted into a secondary form of energy which can then be used on site to power the building. The consumption of primary sources is not reflected in a building’s