What did Willis Haviland Carrier invent?

Willis Haviland Carrier (November 26, 1876 – October 7, 1950) was an American engineer, best known for inventing modern air conditioning. Carrier invented the first electrical air conditioning unit in 1902. In 1915, he founded Carrier Corporation, a company specializing in the manufacture and distribution of heating, ventilation, and air conditioning (HVAC) systems.

In Buffalo, New York, on July 17, 1902, in response to an air quality problem experienced at the Sackett-Wilhelms Lithographing & Publishing Company of Brooklyn, New York, Willis Carrier submitted drawings for what became recognized as the world's first modern air conditioning system. It was so humid in summer that the paper grew and shrank, which resulted in poor quality images, because the color printing process involved running the same piece of paper up to four times, each with a different color ink.

For his contributions to science and industry, Willis Carrier was awarded an engineering degree by Lehigh University in 1935 and an honorary Doctor of Letters degree by Alfred University in 1942; Carrier was awarded the Frank P. Brown Medal in 1942; and was inducted posthumously in the National Inventors Hall of Fame (1985) and the Buffalo Science Museum Hall of Fame (2008).