An air curtain, also known as an air door, creates an invisible door that effectively separates ideal indoor and outdoor temperatures. They work by adding a streamlined, fast-moving air stream to prevent air penetrating through the open doorway.
By creating an air partition between two areas, it prevents outdoor air from entering and indoor air from escaping. This helps the HVAC system work more efficiently by protecting the air conditioned facilities. This in turn reduces overall energy costs (scientific study).
The latest technology allows air doors to work systematically and maintain the optimum balance between velocity & volume. Having an optimized balance allows air doors to operate at a more comfortable sound level.