This paper describes the measured performance of variable air volume (VAV) boxes. Tests were performed to measure the pressure independence, linearity, and hysteresis of boxes produced by three different manufacturers. Results indicate that none of the boxes was able to meet the manufacturer's claimed performance specifications. Performance also varied from manufacturer to manufacturer; thus boxes are not interchangable. Tests show that all boxes required approximately one inch water gauge static pressure to operate properly. Results also indicate that field calibration of boxes will be necessary.

Units: Dual