These are those high velocity air streams that blow across open doorways such as in a mall or casino, so that things look "open" with doors in the way.
Supposedly they block transfer of inside/outside air and reduce the heating/cooling load compared to what a simple opening would create.
I have my doubts.
Anyone have any pointers as to whether these really do anything useful aside from wasting even more heating/cooling/duel/money?
Thanks