Wall-mount ventilation fans circulate air in indoor spaces where fans cannot be mounted to the ceiling. The fans help maintain indoor air quality by pulling in fresh air or exhausting out stale air from indoor spaces. They also may help regulate the indoor air temperature since they circulate the air. Panel exhaust and supply fans are general purpose fans commonly used for ventilating factories, light manufacturing plants, warehouses, schools, storage facilities, and other indoor areas. Shutter-mount exhaust fans have built-in shutters that close when the fans turn off, which blocks out drafts and helps maintain the efficiency of the building's HVAC equipment in garages, barns, and other areas where the fans are installed. Guard-mount exhaust fans feature guards that protect the fans' blades from light impacts and help prevent large debris and other objects from entering the fans.