Revolving Doors!

I recently ran across this great article on why revolving doors save so much more energy than normal swing doors. I'll leave the technical details to the cited article, but suffice it to say revolving doors are wayyyyyyyyyy more energy-efficient.

I've noticed that in Chicago many street-facing doors are, in fact, revolving doors. Given how cold (and windy!) it gets in Chicago in the winter, this makes perfect sense to me. Who among us has not sat in a coffee shop near the door during winter, only to be blasted by the frosty cold when someone opens the door!?

All of which makes me wonder why there are so few revolving doors in Minneapolis. Surely the winters are cold enough here to warrant it. Are they very expensive to install? Wouldn't the energy savings in winter offset the additional installation cost? Maybe the city could incentivize such construction...