Revolving Doors Have An Interesting Purpose

Or at least more interesting than you were thinking.

You know what’s fun? Looking at some random thing in the world and asking yourself, “who was the first person to come up with that, and why?” Cheese, for example, is a fun one; who was the first person to look at a rotten lump of old milk and say “I’m going to eat that?”

For another example, consider revolving doors. Who was the first person to look at a door and say “I’m going to make that spin?” Well, as it turns out, I actually have an answer to that one: Theophilus Van Kannel. There’s an old rumor that Van Kannel invented revolving doors because he hated the concept of door-chivalry. To be more specific, he hated coming up to a door at the same time as someone else and being locked in a brief battle of wits to see who the bigger gentleman was.

Now, unfortunately, this isn’t actually true, but it’s an amusing thought, isn’t it? Van Kannel actually invented the revolving door for energy conservation. Back in the day, it wasn’t cheap to heat or air condition an entire building, so when people opened doors and let the air out, that was money flying out with it. Revolving doors created vacuum seals that prevented conditioned air from leaking out of lobbies, which saved a bundle on energy costs.

Even if an invention sounds silly when you look at it in a vacuum (pun intended), there’s almost always some kind of good, economical reason for it. I’m sure whoever ate the first piece of cheese knew exactly what they were doing. Y’know, probably.