Revolving doors can be clumsy, but once you learn the good that they do to help the environment, you’ll rethink how you feel about them. Invented in the late 19th century, revolving doors were originally called Tür ohne Luftzug in German, or literally “door without draft of air.”
Eliminating that draft was a big deal then, but even more essential now: With the invention of air conditioning, plus the popularity of high-rise buildings, revolving doors help save energy and reduce carbon emissions. In fact, one MIT study in 2006 breaks down exactly how much energy you save by using a revolving door a single time: It equals about 36 watt hours of energy (or enough energy to light a 60-watt light bulb for about half an hour). That might not seem like much, but calculate the hours based on a single building on campus and the number of people entering and leaving, and it adds up. The same study discovered if every person used a revolving door each time he or she entered, the building would save about 80,000 watt hours of energy. Considering office buildings in the U.S. account for nearly 40 percent of energy usage (not to mention 72 percent of electricity consumption and 32 percent of CO2 emissions), a revolving door makes a meaningful impact.
That is, if people choose to use them. Despite the general agreement that using revolving doors goes a long way in cutting down energy costs — and lowering CO2 emissions — the MIT study found that only 20 to 30 percent of people use them when presented the option. Learn how revolving doors help decrease the “stack effect” to save the environment — you might rethink which door you choose.