Courtesy BTHL

This post is part of a monthly series that explores the historical applications of building materials and systems through resources from the Building Technology Heritage Library (BTHL), an online collection of AEC catalogs, brochures, trade publications, and more. The BTHL is a project of the Association for Preservation Technology, an international building preservation organization. Read more about the archive here.

The start of the summer is often marked by two events: the changing school schedule and the switch from heat to air conditioning. While civilizations have manipulated their built environments to keep out heat for centuries, the modern air conditioning unit was not developed until the early 20th century. In 1902, American engineer Willis Carrier—charged with improving magazine-page wrinkling caused by heat and humidity at the Sackett-Wilhelms Lithographing & Publishing Company of Brooklyn, New York—succeeded in developing a mechanical unit that circulated cold water through metal coils, controlling air moisture and temperature. And though this innovation was created for industrial efficiency, it also proved beneficial for worker comfort.

Just two years later, the public first experienced comfort cooling at the 1904 World’s Fair in St. Louis with mechanical refrigeration at the Missouri State Building—and so began the growth of air conditioning in the U.S.

Movie theaters were among the first businesses to understand the marketing advantage of a cooled interior space in the 1920s, while air conditioning for residential applications followed soon after in the 1930s. Though not a simple conversion for residences—millions of houses were heated with boilers or radiators and the addition of air conditioning units meant the movement of cooled air rather than hot liquid—the simultaneous growth of the sheet metal industry facilitated the proliferation of air conditioning units.

With examples of large- and small-scale units in various applications, the BTHL chronicles the birth and expansion of the air conditioning industry.

Artificial Refrigeration : Carré’s and Mignon & Rouart's Continuous Freezing Apparatus for The Production of Ice by the Direct Action of Heat, M. J. Bujac, New York, 1870

This 1870s publication reveals the technical and commercial origins of artificial refrigeration in the era before electricity. The production of ice by the direct action of heat was a marvel of modern engineering.

Carrier Air Washers and Humidifiers: With Notes on Humidity, Carrier Air Conditioning Company of America, New York, 1908

The Carrier Air Conditioning Company of America—founded in part by Willis Carrier in 1915—was a leader in the production of air conditioning units. By the 1950s, the company began marketing their products for residential applications and is considered a major contributor to suburban sprawl in areas such as the American Southwest by providing improved living conditions in once-remote regions.

Theatre Cooling by Carrier: Centrifugal Refrigeration and Air, Carrier Engineering Corporation, New York, 1925

Movie theaters were quick to take advantage of this new technology—and many manufacturers began to market cooling units as essential to the movie-going experience. “Summer heat has always been the theatre’s chief competitor,” this publication writes. “The day is here…when to the regular theatre investment of land and building will be added that of a refrigeration plant. It will be a necessity.”

The Carrier Unit Air Conditioner: Manufactured Weather and Industry, Carrier Engineering Corporation, New York, c. 1928

The unit air conditioner by Carrier made it possible to cool a single, smaller space compared to larger industrial units of the day. This was particularly useful in renovation projects, as many older buildings were heated with boilers and radiators and the addition of air conditioning required a different distribution system.

“It's in the air!” A better World in Which to Live and Work, General Electric Co., c. 1938

“From now on all truly modern homes must be air conditioned” is the proclamation in this General Electric catalog from the 1930s, which provides both technical details and testimonials. Central air conditioning became a new option with the development of small scale equipment that integrated air conditioning into furnaces.

Comfort Cooling by Attic Ventilation, American Blower Co., Detroit, 1938

Though large exhaust fans were used to cool residences with moving air, they did not provide any dehumidification. This unit is marketed specifically for residential attic spaces and advertises the fan as cooling "with nature-conditioned air."

Mountain fresh...Ocean Bathed: Climate at Home, Fox Furnace Co., Elyria, Ohio, 1938

“There is no need to go south in the winter and to the mountains or shore in the summer” writes this publication. “With a modern air conditioning system creating a mountain-fresh, ocean-bathed climate at home.”

Air conditioning for Your Home by Sunbeam, American Radiator & Standard Sanitary Co., Elyria, Ohio, 1939

“Conditioned air is as vital as pure food” was the sales slogan for Sunbeam air conditioning. This catalog emphasizes the health benefits of furnaces with humidification, filters, and cooling capabilities.

Air Conditioning and Refrigeration in Baltimore and the South, Paul J. Vincent Co., Baltimore, c. 1940.

This testimonial publication showcases regional projects by Paul J. Vincent Co. The examples highlight the importance of movie theaters as “pioneers” in introducing cooling systems, with claims that costs associated with installing and sustaining an air conditioning system would pay for themselves in two years. Additionally, this catalog also argues that cooling units in restaurants can increase sales by 300 percent, attract tenants to office buildings, and improve productivity in industrial plants.

Mueller Climatrol, L. J. Mjeller Furnace Co., Milwaukee, 1953

The L. J. Mueller Furnace Co. line of products included both cooling equipment and “winter air conditioning,” which incorporated humidification system with a furnace for the winter months.