Faults occurring in improper routine operations and poor preventive maintenance of heating, ventilating, air conditioning, and refrigeration systems (HVAC&R) equipment result in excessive energy consumption. An air-handling unit (AHU) is one of the most extensively operated equipment in large commercial buildings. This device is typically customized and lacks of quality system integration, which can result in hardware failures and controller errors. This paper aims to provide a systematic review of existing fault detection and diagnosis (FDD) methods for an AHU therefore inspire new approaches with high performance in reality. For this goal, the background of AHU systems, general FDD framework and typical faults in AHUs, is described. Ten desirable characteristics used in a review of FDD in chemical process control are introduced to evaluate the methodologies and results. A new categorization method is proposed to better interpret the different and most recent approaches. The main FDD methodologies and hybrid approaches are described and commented to illustrate the use of evaluation standard parameters for improving the performance of FDD on AHUs. (C) 2014 Elsevier B.V. All rights reserved.