Slate again with a piece about the environmental efficiency of revolving doors. Turns out they are pretty good at not letting too much air-conditioned air out, or too much cold air in during the winter.

Revolving doors are so popular in midtown that I walk through them at least eight times a day. But I'm always a bit annoyed by the resistance built into them to keep them from picking up too much speed. Why not make them even better for the environment by harnessing that energy and making a human turbine?