The low-flow fume hood cuts energy use by 40 percent, and is coupled with implementing fume hood occupancy controls, which automatically turn off fume hoods when they are not in use. Washington University in St. Louis helped to develop these fume hoods, which were exceptionally useful in the Lab Sciences Building, where nearly 300 fume hoods are in use. There was insufficient capacity in the steam and chilled water system to support this number of fume hoods using conventional consumption.