Cooling off on a hot day is easier than you might imagine

Remember being told that fanning yourself on a hot day actually makes you hotter?

Not at all, says theoretical astrophysicist, Dr. E. Sterl Phinney. In fact, he explains that fanning cools you off more than you might think.

In a Wall St. Journal report, he breaks down the fanning effect by the numbers.

Amount of energy you produce while at rest… about 100 watts.

Waving a fan adds… about one watt.

The result… coolness is doubled.

The trick, according to Dr. Phinney, is to reduce the boundary layer. That’s the layer of motionless air between your skin and the air around you. Fanning makes the boundary layer thinner. And you feel significantly cooler.

For only one watt of effort, you can’t go wrong.

But Dr. Phinney has a suggestion for even better results. With a minimum of effort (not including the installation), a porch swing creates a wraparound breeze to thin even more of your boundary layer.

Pretty cool.

Sources:
“Does Fanning Help on a Hot Day?” Heidi Mitchell, Wall St. Journal, online.wsj.com