Green Tip of the Month: Choose the Revolving Door
In 1899, the world’s first wooden revolving door was installed at Rector’s, a restaurant in Times Square on Broadway between West 43rd and 44th Streets. Prior to that, H. Bockhacker of Berlin was granted a German patent in 1881 for “Tür ohne Luftzug” or “Door without Draft of Air” and Theophilus Van Kannel, of Philadelphia, was granted a U.S. patent in 1888 for a “Storm-Door Structure.”
Disrupt the flow
Air flows in and out of a building because of differences in air pressure — in the winter, heated air rises toward the top of a building, and cold air rushes in through open doors to replace it. The opposite happens in the summer, with the cold air flowing out the open doors. Entering and exiting through a revolving door allows for much less air exchange and fuel use, and saves up to 30% in energy costs.
Reduce the loss
Using a revolving door instead of a swing door saves about 267 BTUs of heat energy, roughly equivalent to 1.3 hours of light from a incandescent lamp, 4.3 hours of light from a compact fluorescent bulb or .06 miles of fuel for an automobile.
Did You Know?
A crack as small as 1/16th of an inch around a window frame can let in as much cold air as leaving the window open three inches.