To analyze energy consumption and estimate the cost-ešectiveness of energy conservation measures, an auditor can use a myriad of calculation methods and simulation tools. ˜e existing energy analysis methods vary widely in complexity and accuracy. To select the appropriate energy analysis method, the auditor should consider several factors, including speed, cost, versatility, reproducibility, sensitivity, accuracy, and ease of use (Sonderegger, 1985). ˜ere are hundreds of energy analysis tools and methods that are used worldwide to predict the potential savings of energy conservation measures. In the United States, the DOE provides an up-to-date listing of selected building energy so¬ware (DOE, 2009).