Air curtains: selection parameters

Air curtains — air currents generated by special devices designed to protect premises from air currents, dust and insects penetrating through window and door openings. Such devices are installed from above (over a door, window or other opening) or from the side (there are horizontal and vertical curtains, respectively). The devices create a powerful air flow - in the summer it will not let heat and dust into the room, and in the winter - cold.
Due to the described possibilities, air curtains are quite popular, but the choice among them is not as simple as it seems at first glance. Before buying this or that model of curtain, you should pay attention to the optimal installation height, its power and length.
Installation height and its calculation

The speed of a properly installed curtain is 8-10 m / s at the exit from the device and about 3 m / s at floor level. But this is only possible if the unit is installed at the correct height from the floor.If the curtain is installed higher than necessary, the device will not be able to provide the necessary flow parameters and a layer of unprotected space will appear near the floor for the penetration of cold air. Most curtains have special elements that allow them not only to interrupt the internal climate, but also to warm the room - so that gas heating boilers or any other heating method become redundant.
Costs for curtains quite high, largely depends on which fan is installed inside. Sometimes plant growers, in an effort to save money, install two short fans instead of one long one, or make the outlet nozzle too narrow. In the first case, an engine is located between two short fans, as a result of which there is a «immersion» in the air flow. If the nozzle is too narrow, the curtain is thinner than it should be, and the wind is not difficult to "break" into the room.
Curtain power
Power is not a defining characteristic, as the curtain's protective characteristics depend on its speed. However, if the air flow plays the role not only of a barrier, but also of a heater, the power becomes an important indicator.
A curtain without heating functions is called "air" - it serves only as an obstacle without affecting the microclimate inside.
Tool length
The length of the device should be slightly greater than or equal to the width of the door or window. A device with a length of 800-900 mm is suitable for an ordinary door, and a device with a length of 1.5-2 m may be required for a garage door. If the opening is very wide, it is better to install a vertical curtain (they are installed on the side, not on top).