16. “Air Curtains” were predicted to one day render traditional doors obsolete
Promoting the total elimination of doors for stores, at least during day-time with “a conventional door” fitted during closed hours, the “curtain of air” would provide “downward-rushing air” which “acts as a temperature and draft barrier to protect the interior”. Achieved by “rows of overhead nozzles” which would “direct filtered, warmed, (or air-conditioned) air downward”, “the air velocity” would serve as a “gentle breeze that won’t disturb women’s hair” but simultaneously strong enough to “keep out dogs and cats”.
Although the initial reaction to this technological prediction is perhaps incredulity and scorn, it might amaze that the “air door” is now actually a common feature of modern day life. Whilst old-fashioned doors themselves have not been removed in the manner assumed, the air curtain as described in the 1950s has been routinely fitted on a range of public buildings from shops, to airports, and even restaurants. Preventing air or contaminants from passing from one space to another, modern “air doors” work to maintain as neutral temperature and pressure difference as possible between the interior and exterior to impede natural dispersion. Not only increasing the cleanliness and preventing insects from entering, but this method also reduces the heating requirements of the establishment by decreasing lost heat. It is estimated that an air curtain pays for itself in saved heating bills after only a few years of operation.