Data on the performance of fan/motor combinations usedin fan-powered terminal units (FPTUs) were evaluated, andrelationships were developed between fan/motor efficiencyand fan total pressure as well as fan motor power and fanairflow. All fan motors were permanent split capacitor, with thespeed of the motors being altered with silicon-controlled rectifiers(SCRs). Three manufacturers provided detailed experimentaldata on 12 fan/motor combinations employed incommercially available FPTUs. The fan motors ranged in sizefrom 1/8 hp (93W) to 1 hp (746 W). The maximum fan airflowsranged from 690 to 4524 ft3/min (0.33 to 2.14m3/s). Data werecollected by each manufacturer and provided to the authors.The performance data included SCR voltage, discharge staticpressure, airflow, volts, amps, volt-amps, power factor, power,motor speed, motor size, and power divided by airflow. Datawere also provided on fan discharge area and motor size. Alinear relationship between fan/motor total efficiency and fantotal pressure was inferred for the units evaluated. By use ofthe definition of “fan efficiency,” it was also shown that therelationship between fan motor power and fan airflow shouldalso be linear. The correlations developed should be in a formthat can be readily used in energy simulation programs tobetter estimate the performance of FPTUs.