Air conditioning was invented in 1902 by Willis Haviland Carrier. He needed to solve a problem that a printer in Brooklyn, New York, was having with controlling the humidity in his premises. He discovered that if he reduced the temperature then he could also reduce the humidity and in so doing invented air conditioning.

Other early applications included film production, tobacco, processed meats, medical capsules and textiles.

Cooling for human comfort, rather than industrial need, began in 1924, when three chillers installed in the J.L. Hudson Department Store in Detroit, Michigan, had shoppers flocking to the 'air conditioned' store. The boom in human cooling spread from the department stores to the movie theaters, most notably the Rivoli theater in New York, whose summer film business skyrocketed when it heavily advertised the cool comfort.

In 1928, Willis Haviland Carrier developed the first residential 'Weathermaker', an air conditioner for private home use.