If you make a point of minding your manners, revolving doors are a terror. Should a man go in first to get things rolling for his female companion? Or does the “ladies first” rule still hold? It’s no accident that this question comes up any time you approach a revolving door—revolving doors were actually invented to inspire this moment of indecision.

According to some etiquette buffs, it’s proper form for a man to open doors for a woman, allowing her to enter and exit before he does. But in the case of revolving doors, this standard rule of chivalry does a 180, if you will. Men should go first through the revolving doors, as Park Hyatt Chicago doorman Joe Snyder told Real Simple: “A gentleman should always go first and assist the woman through the revolving door, and I observe this on a daily basis.” This relieves women of the effort of pushing the door open and is ultimately considered a more polite move. Chivalry isn’t dead, but it’s been updated for modern times.

As it turns out, this polite gesture would crush the feelings of the revolving door’s creator, Theophilus Van Kannel. It is said that he so disliked the social convention of men opening doors for women that he invented a new type of entrance in attempt to sidestep the issue. Luckily for Van Kannel, he also had the scientific chops to back it up, even if he was inadvertently creating a new rule in the original one’s stead.

On August 7, 1888, the Philadelphian first patented the “storm-door structure” that we know today as the revolving door. Building upon H. Bockhacker’s German patent for “Tür ohne Luftzug” or “Door without Draft of Air” introduced in 1881, the world’s first revolving doors were installed at Rector’s, a restaurant in Times Square, in 1899. Over a century ago, Times Square was the epicenter of technology and change, whereas today it is synonymous with life-size cartoon characters and bad jokes about tourists (more proof that our world is not the one Van Kannel once knew).

Thankfully, Van Kannel’s invention had a purpose beyond relieving his anxieties. Revolving doors contribute to keeping a building energy efficient by regulating its temperature and air pressure. Imagine it’s a summer day and the air conditioning is pumping. When a door swings open, the cold air rushes out and hot air rushes in to fill the void, and the building’s cooling system must overcompensate to make up the difference. The same thing happens in the winter, but in the opposite order. Thanks to the design of revolving doors, much less air rushes out when people exit and enter through them. The benefits of revolving doors don't end there: they also keep out street noise and fumes.

When revolving doors replace swing doors, they can save up to 30 percent in energy costs, or as Rockefeller University explains, “267 BTUs of heat energy, roughly equivalent to 1.3 hours of light from an incandescent lamp, 4.3 hours of light from a compact fluorescent bulb or .06 miles of fuel for an automobile.”

Despite the unequivocal benefits of using revolving doors, a 2006 MIT study found that only 20 to 30 percent of people use them when presented with the option. A few years later, New York City designer Andrew Shea set out to remedy this trend on his own turf where he noticed similarly low utilization of revolving options. Shea posted signs at Columbia University touting the environmental gains of using revolving doors. With his encouragement and some neat facts—like how revolving doors can save 14.6 tons of carbon annually—usage of revolving doors at Columbia skyrocketed from 28 to 71 percent.

In the years following his invention, Van Kannel would go on to own The Van Kannel Revolving Door Co., which he later sold to International Steel before becoming the International Revolving Door Company. You may not be surprised to learn that he never married, but rather dedicated the rest of his life to improving his creation. Van Kannel did enjoy acclaim for his doors in his lifetime, receiving Philadelphia's John Scott Medal for his invention's usefulness to society. He was inducted into the National Inventors Hall of Fame in 2007 for his accomplishments. Hopefully everyone used the revolving doors when entering and leaving the ceremony.