Green buildings aim to save land, energy, water, and material, as well as to create a healthy and comfortable environment for their occupants throughout the life-cycle. One of the primary goals for the design of green buildings is reducing operating energy costs. Mainly due to the energy performance requirements of various green building rating systems, building energy modeling (BEM) is being increasingly used in the building industry, which definitely improves building energy efficiency through code and standard compliances. However, as a scientific and standardized method, using BEM can provide far more benefits than just code and standard compliances. BEM can be used for many other purposes at different stages of the building lifecycle.