Comprehensive building retrofits require an investment grade audit in conjunction with a calibrated hourly energy model. Even with the most thorough audit processes, uncertainty still remains when identifying and modeling building parameters. This uncertainty propagates throughout the final calibrated model and affects the quality of the energy saving estimates. This paper, geared towards the typical energy analyst, provides a step-by-step process for achieving more reliable results by calibrating an energy model based on actual utility data. This paper presents the following: a list of essential pre-audit activities, including a robust energy audit checklist containing crucial information for accurate energy models; a process for calibrating an energy model to actual utility data; and, a summary of statistical methods to evaluate the strength of the calibration. This step-by-step process provides a user-friendly reference for energy modelers to create accurately calibrated energy models with minimal time investment.This article or paper was published in ASHRAE Transactions, 2010, vol 116, part 2. Copyright 2010 American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc. Reprinted by permission at www.rmi.org. This article may not be copied and/or distributed electronically or in paper form without permission of ASHRAE. For more information about ASHRAE Transactions, visit www.ashrae.org.