The results of a study aimed at improving the performance and fife expectancy of air-conditioning systems at a S.audiArabian university are presented. These results are based on an investigation of the service records of about 3000 air-conditioning systems ranging from 1.5 to 200 tons (5 to 700 kW). All the systems considered are of the air-cooled type. Both statistical and physical aspects of system failure are analyzed and reported. The study found that a substantial number of failures are caused by improper maintenance of equipment and the adverse local environment, which is corrosive, dust-laden, and experiences high ambient temperatures.