One of the biggest technological advancements in movie theatre history had nothing to do with what was happening on the screen. As this incredibly comprehensive article on the history of commercial air conditioning details, theatre owners knew that summertime meant a drop in patronage due to the close, overheated quarters. When air conditioning became available, theatres were early adapters and air conditioning was suddenly a major advertising pull. Theatres would devise their systems to pump air out of the auditiorium through the lobby and onto the streetfront, hoping to lure in patrons with what engineers called “advertising air”

Willis Haviland Carrier, widely regarded as the inventor of the first modern air conditioning system,  gave this recollection of a 1925 air conditioning installation at the Rivoli Theatre in New York.

Long before the doors opened, people lined up at the box office—curious about ‘cool comfort’ as offered by the managers. It was like a World Series crowd waiting for bleacher seats. They were not only curious, but skeptical—all of the women and some of the men had fans—a standard accessory of that day.
It takes time to pull down the temperature in a quickly filled theater on a hot day, and a still longer time for a packed house. 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. We then went into the lobby and waited for Mr. Zukor [the president of Paramount Pictures] to come downstairs. When he saw us, he did not wait for us to ask his opinion. He said tersely, “Yes, the people are going to like it.

As the linked article states, the air conditioned Rivoli Theatre made $100,000 more that summer than it had the previous.

(credit: American Theatre Architecture Archive, Theatre Historical Society of America)