At the turn of the 20th century, humidity threatened the reputation of Brooklyn’s Sackett-Wilhelms Lithographic and Publishing Company’s high-quality color printing. After two summers of extreme heat disrupted business and caused swelling pages and blurry prints, the printing company found that a nascent cooling industry could offer help.

Willis Carrier, a 25-year-old experimental engineer, created a primitive cooling system to reduce humidity around the printer. He used an industrial fan to blow air over steam coils filled with cold water; the excess humidity would then condense on the coils and produce cooled air.