Ventilation in many agricultural livestock and crop buildings and structures is crucial to maintain animal health or crop quality. Agricultural operations may have large numbers of ventilation fans operating for extended time periods making ventilation a large electrical consumption end use. Unlike other electrical energy?consuming equipment, there is little opportunity to manage operational schedules and electrical use of ventilation fans on a daily or seasonal basis without severely affecting operational management and having adverse effects. Improving the energy efficiency of an agricultural fan is the only practical way to reduce electrical energy use for ventilation. Energy efficient ventilation fans use less electrical power to move equivalent amounts of air, resulting in energy savings. This Engineering Practice is intended to provide information helpful in making decisions involving selection of energy efficient ventilation fans in agricultural operations.