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Revolving Doors

Having grown up in rural Maine, I still get a little thrill every time I go through a revolving door. (Escalators, too, but that’s a different story.) So I can’t understand why some people seem to avoid them at all costs. In my office building I’d say about half of the people detour to the regular doors.

But you know the signs some buildings put up—”To conserve energy, please use revolving doors”? They’re actually true.


Each time we open a door, air is exchanged between the inside of the building and the outside. An MIT student group’s study showed that revolving doors exchange 8 times less air than swinging doors. They found that the average heat transfer when a swinging door is used was 267 BTUs (or 78 Wh, roughly the equivalent of using your laptop for an hour and a half). Of course, the effect is worse during extreme hot or cold, or on windy days, with the most effective use of a revolving door being when it’s both cold and windy.

Over time, those energy savings can really add up. And switching which door you use takes almost no effort. How often do we get handed a win that easy?


Comment from Brian B
Time October 1, 2009 at 12:36 am

Now if they could use the energy people wasted pushing the door all day to supply electricity to the building that would be cool.

Comment from Brenda Pike
Time October 1, 2009 at 7:46 am

This exists! A place called Fluxxlab invented it.

Comment from Sharon
Time October 3, 2009 at 9:39 am

It’s not just winter–in summer when they’re using WAY TOO MUCH AC inside, it’s probably just as bad as letting the heat out in winter.

Here’s a semi-related question: if every mall in America turned the AC down just five degrees, how much power would that save? Never mind the heat–just the unnecessarily frigid cool.

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