Air curtains keep two environments seperate by preventing the intrusion of flying insects, dust, and other airborne contaminants and by keeping inside conditioned or heated air untainted by outside air

Air doors create an invisible air seal generated by high-efficiency, direct-driven centrifugal fans that compress air inside the unit and release it through a directional nozzle outlet with a pressure designed to be powerful enough to stop winds up to 25 mph.  An air curtain, used for repelling flying insects, requires a higher velocity of air than one designed for environmental preservation.

Air curtains are available with adjustable air velocities and operators can purchase them unheated or equipped with electric, steam, or hot-water heating units.  Industrial models are available with gas-fired heating options. 

Air curtains repel houseflies and other pests, helping to eliminate potential exposure to diseases.  The FDA specifically recommends the use of air curtains for the exclusion of insects.  Several states have additionally enacted legislation regarding the mandatory installation of air curtains at specified openings in food production facilities.