Below is a list of Ventilation Fans manufacturers from Cincinnati, Ohio. Ventilation fans are air blowers that are used to move air through ventilation systems. They are essential components of HVAC systems, without which it would be very difficult to circulate air through buildings. Ventilation systems are used to evacuate harmful or unpleasant gasses from workspaces, they are used to supply warm or cool air to homes and they keep indoor air fresh.