Whole Building Energy Modeling is the energy analysis to estimate the building energy use. It’s often performed for the comparative analysis of design trade-offs to meet the predefined energy goals. Also, it’s an important part of the energy rating process, particularly when combined with the air tightness verification in the field.  Required by many energy conservation building codes for energy trade-offs. Energy modeling and simulation is an absolute must for the green building and more generally for energy efficient houses. 
thermal balance