Agent based modeling (ABM) is a method of modeling complex systems that allows for detailed, endogenous actors interacting with one another and with their environment based on predefined agent rules and goals. ABMs allow modeling at a desired aggregation level that is most conducive to producing realistic market trends at the aggregation level desired. As ABMs obtain market trends based on individualistic goals of agents, they are an ideal tool for short term and long term market trend analyses. Argonne National Laboratory has developed and recently validated the Commercial Building Agent Model (CoBAM), an ABM with both a commercial and residential building stock. An example showing the power of CoBAM in evaluating the energy savings due to adoption of energy efficiency measures is included.