When a tech company recently came to Stefano Schiavon at the University of California, Berkeley to test an air-conditioning system for its office, his mind went to flip-flops. The new system would blast cool air from the floor rather than the ceiling, and this being the Bay Area, and this being a tech company, Schiavon figured he couldn’t use the same old models researchers have been using since the 70s to study thermal comfort. (Yes, that is the name for the academic study of maintaining a building at just the right temperature.)
He needed to test people in flip-flops.
Feet, it turns out, are exquisitely sensitive to temperature. When you get cold, the blood vessels in your extremities are the first to constrict, which is your body’s way of preventing more heat loss. “You feel uncomfortable because your feet get numb or getting close to numb,” says Edward Arens, an architect at the University of Berkeley, who also studies thermal comfort. If building managers could heat or cool the feet alone, they could cut energy and costs. So at Berkeley, researchers are focusing on thermal comfort from the feet up.