It's easy to think that the days before air conditioning were hellish. And sure, compared to the perfectly climate-controlled spaces we have today, life was pretty sweltering during the summer months. But it wasn't as sweltering as you might think. That's because without air conditioning, people came up with other ways to cool down. They kept blocks of ice in their homes — purchased from enterprising merchants who saved it for months in cool basements — and often spent more time outside in the fresh air. And while modern dwellings often have low ceilings and windows that don't open, buildings before A/C made liberal use of windows, awnings, and other inspired design touches that helped ventilate heat.

Of course, a movie theater can't do that. To maintain the lack of light and outside noise you need for the silver screen, you can't have windows or vents or any other nicety that might let out the heat. As a result, a summer movie required sitting in a dark, sweltering room next to hundreds of other sweating bodies with a paper fan as your only relief. No wonder ticket sales dropped in summer.

The tale of the first air-conditioned movie theater is almost mythical. The story goes that in 1925, a young engineer named Willis Carrier installed a newfangled cooling contraption in the Rivoli Theater, Paramount Pictures' showpiece on Times Square in Manhattan. The crowd was skeptical at best, and all brought folding fans in their anticipation of a sweltering movie theater like every other they'd attended. But in the end, the trial run was a success, and soon Carrier was installing air conditioning in theaters across the nation.

Like the story of many great inventions, this one is a bit of a tall tale. The truth is that the world was familiar with the concept of mechanical cooling devices for decades before that trial run in the Rivoli Theater, though much of it was thanks to Carrier himself. As far back as 1902, he had designed the first cooling coils — the predecessor to modern air conditioners — to help a publishing company dealing with paper damage from heat and humidity. And even movie houses weren't new to the idea of artificial cooling, as they'd been using fan-powered ice boxes to cool theaters for years, although those systems struggled to lower the temperature by even a few degrees.

Carrier was also pretty successful by the time of that fateful night at the Rivoli. His groundbreaking centrifugal refrigeration machine was already installed at several candy companies and many fancy department stores throughout the nation. Then came the movie theaters: Sid Grauman's Metropolitan Theatre in Los Angeles installed Carrier's machine as an upgrade from its old ammonia-powered system, then two theaters in Texas became the first to install Carrier's complete system. The Rivoli was historic not because it was the first, but because it was the most important. Carrier had tried his production "off-Broadway," and the Rivoli Theater was his big premiere.

Even with all that lead-up, however, Carrier did recall that audience members weren't entirely trusting: "They were not only curious, but skeptical — all of the women and some of the men had fans — a standard accessory of that day." Then, the big moment: "Gradually, almost imperceptibly, the fans dropped into laps as the effects of the air conditioning system became evident. Only a few chronic fanners persisted, but soon they, too, ceased fanning. We had stopped them 'cold' and breathed a great sigh of relief."

But even as Carrier's contraption spread to office buildings and rail cars, the systems were expensive and cumbersome and therefore slow to be adopted by the masses at home. As a result, the movie theater became the only place that many people had to escape the punishing heat. As theaters filled during the summer, movie studios rethought the way their films would be released — and summer movie season was born.

Get stories like this one in your inbox or your headphones: sign up for our daily email and subscribe to the Curiosity Daily podcast.

The story of air conditioning isn't all good news. Check out "Cool Comfort: America's Romance with Air-Conditioning" by Marsha Ackermann to see how A/C changed the world — and not always for the better. We handpick reading recommendations we think you may like. If you choose to make a purchase, Curiosity will get a share of the sale.