ABSTRACT A calibration procedure for simplified building energy simulation models for commonly used HVAC systems has been developed through an ASHRAE-sponsored project (ASHRAE RP-1092). The procedure is applied to five buildings. These five buildings include a 44-story office building@ a low-rise office building@ a church@ a university teaching building@ and a university research building. Three of the five buildings are located in Omaha@ Nebraska (cold climate). Two buildings are located in College Station@ Texas (hot and humid climate). This paper presents the calibration procedure and summary results of five case studies. A two-level calibration procedure provides a good approach for model calibration. The case studies strongly indicate that the simplified model calibration procedure developed can be used to accurately calculate long-term energy consumption data using short-term field energy measurement data for different types of buildings with different systems. The first-level calibration procedure is very important and improves the model accuracy significantly. The average absolute value of NMBE decreased from 41% to 6%@ and CV(RMSE) decreased from 63% to 26% for these building models after the first-level calibration. The second-level calibration procedure further reduced these values to 2.5% and 22.4%@ respectively. After calibration of the simulation using four weeks or less of measured hourly data@ the average of the absolute values of the prediction error for annual consumption values was 2.5%@ with a maximum error of 9% for the case studies examined. General information on the building and HVAC systems are the most critical input parameters for the simplified model calibration. Short-term hourly chilled-water consumption and hot-water consumption are the most critical energy data for calibration.