In the following article we explore the early history of air-conditioning from the late nineteenth century to the 1930s, just before the start of the Second World War. Reyner Banham noted that in the late nineteenth and early twentieth centuries, the heating, cooling and ventilating industries and their engineers were “oriented almost entirely towards improvements in factory environments, because there alone were the problems big enough, and profitable enough, to bring the manufacturers of plant and its users together in situations where the economic advantage to both sides were clear enough” (Banham 1984, 174). Indeed, two of the three pioneer engineers who played important roles in building sophisticated mechanical systems for controlled indoor environments were mainly involved in factory environments. The first is Stuart Cramer, a textile mill engineer from Charlotte, North Carolina, who coined the term air-conditioning in 1904. Cramer used air-conditioning to describe his method of atmospheric humidification of textile mills. Humidity control was important in factories that processed hygroscopic materials, i.e. materials that absorb moisture from the air. It was important for cotton and wool to absorb moisture in the mills as they became easier to spin and weave. The introduction of mechanised weaving in late nineteenth century only made humidity control more important. Cramer introduced a mechanical system that merged ventilation with humidification. Instead of the previous methods of adding moisture to the atmosphere by spraying a fine mist of water that might promote rusting of the machinery, Cramer’s system introduced conditioned humidified air and eliminated the direct use of water. Unlike previous methods, Cramer’s system was able to maintain a precise predetermined level of relative humidity, maximizing control of atmospheric conditions for the optimization of production. Cramer’s system led to the replacement of window ventilation with a mechanical system and started the isolation of the “conditioned” atmosphere of the interior from the outside. Between 1895 and 1918, Cramer’s Company equipped one third of the South’s cotton mills.
The textile manufacturing process was not the only the only one affected by atmospheric humidity. The manufacturing processes of other commodities, such as tobacco, sausage, chocolate, pasta and candy, were also sensitive to atmospheric humidity of the factory environments. Beside Cramer, the “father of air-conditioning” Willis Carrier also started his career with the design of air-conditioning system to control humidity level in factories. Working for Buffalo Forge Company in 1903, Carrier came up with an air washer system to control the humidity level of the printing room of Sackett-Wihelm Lithography Company of Brooklyn so that paper would not expand and shrink due to changing humidity levels and affect the printing process. After Carrier left the Buffalo Forge Company to set up the Carrier Engineering Company in 1915, he continued to design air-conditioning systems for various industrial processes.
In many factories, the atmospheric requirements for efficient processing and production were different from those required for workers’ health and comfort. Before the introduction of mechanical air-conditioning, the only way to regulate both humidity and ventilation was through the opening and closing of windows. In factories that needed to maintain a high humidity level for efficient production, the windows were closed. But having the windows closed meant that the factories’ interior would be ill-ventilated and damp, which was uncomfortable and unhealthy for the workers. If the windows were opened to let in cooling breezes and create a more comfortable environment for the workers, the humidity level would drop and affect the production. These conflicting needs contributed to many management-labor conflicts. Mechanical air-conditioning systems promised to resolve such conflicting needs. This was evident in the tobacco industry. At the American Tobacco Company’s Richmond, Virginia plant, Carrier designed an air-conditioning system that increased the humidity and decreased the amount of dust and particles in the plant, thus improving both the conditions for production and the workers.
The third pioneer in mechanical cooling is Alfred Wolff, who is better known for his installations for comfort cooling. One of his early experiments with comfort cooling was the ventilation and cooling system he installed for Carnegie Hall in 1889. The system he installed combined the use of fans with racks of ice. He later became aware that humidity control, not just temperature control, was important for comfort cooling. His first large scale installation of a cooling system with humidity control was at the Cornell Medical College Building in New York in 1899. The building had a unique cooling system for the postgraduate dissecting room on the fifth floor. The main consideration was to preserve the cadavers during the use of the dissecting room. In that sense, it was like a refrigeration system for the corpse that was patented in 1885. However, the school administrators could not resist using the cooling system for keeping crowds comfortable. After the building opened, graduation exercises were held in the main dissecting room and the door to the postgraduate dissecting room was left opened to allow chilled air out to cool the 1,500 attendees. On such occasions, Wolff noted down the temperature and humidity of the various spaces. Using this data, Wolff carried out further calculations to note how much more capacity was needed to provide sufficient cooling and comfort.
The air-conditioning system installed at the New York Stock Exchange building, completed in 1903, by Wolff was considered as the first truly air-conditioning installation because it regulated both air temperature and humidity. Furthermore, it was designed as an integrated distribution system that cleansed the air too (Cooper 1998, 15). Drawing on all his prior experience in designing ventilation, heating and cooling system, Wolff recognized that humidity was one of the main causes of discomfort and he established 55 percent relative humidity as a standard to strive for. In his calculations, Wolff took into consideration an array of factors that affected heat load, such as the climate data from US Weather Bureau, the heat gain through the building envelope, from the occupants and the equipment in the interior space. This comprehensive approach to calculating heat load first pioneered by Wolff was subsequently considered the norm. The New York Stock Exchange building was completed at a time when buildings were becoming increasing complex machines with all kinds of mechanical and electrical services. Questions surrounding the relationship between architecture and building services would later surface and preoccupy architectural historians and theorists like Reyner Banham, as air-conditioning become ubiquitous. But at the turn of the twentieth century, air-conditioning was still considered an expensive novelty that few outside of the industrial and commercial worlds could afford. Wolff only installed three residential systems, all for superrich clients – Cornelius Vanderbilt, Andrew Carnegie and J. J. Astor.
Banham noted "in practice, few situations where simple human comfort offered a profit margin proportionally large enough to make investment worthwhile, and large enough in absolute terms too, to make investment possible, given the plant then available. Hotel dining rooms and ball-rooms came within this class, as did Pullman cars and – above all – theatres” (Banham 1984, 175). After the various industrial installations for process air-conditioning by Cramer and Carrier and the few cases of expensive installations for comfort air-conditioning by Wolff, one of the first building types to be widely air-conditioned because it made economic sense was the theater. Traditionally, theaters faced environmental problems associated with the concentration of a large number of people within a confined space – heat generated by the people, high level of humidity from inadequate ventilation and high carbon dioxide concentration. Nineteenth century engineers sought to solve these problems using thermal siphons and mechanical fans, either steam-powered or electric. Later, the fan-propelled ventilation system was combined with blocks of ice to cool the air. One of the earliest installation of such a system was at the Madison Square Theater, New York. But such a system tended to be not reliable enough as both air humidity and temperature controlled in a precise and predictable manner. Furthermore, as such a system required large amount of ice and created huge volume of water from the melted ice, it was too cumbersome, messy and labor-intensive to operate.
Two of the earliest theaters to install air-conditioning were two Balaban and Katz theaters in Chicago – Central Park Theater in 1919 and Riviera Theater in1920, Chicago. The engineer Frederick Wittenmeir of Koreschell Brothers Ice Machine Company modified a refrigeration system originally designed for the meat packing industry for the two theaters. The new system used upward distribution, i.e. it supplied cold air through floor-mounted mushroom ventilators. Theoretically the cold air would be warmed to a comfortable temperature and enveloped the patrons before it rose further and was extracted at the ceiling. In practice, however, most of the cold air stayed at the floor level and the patrons complained of drafts and some even resorted to wrapping newspaper around their feet. Nevertheless, the mechanically cooled atmospheres of the theaters became their selling point.
In 1922, Carrier Engineering Corporation installed the air-conditioning system at Graumann’s Metropolitan in Los Angeles. Carrier’s system ventilation system reversed the flow of the chilled air. Instead of having chilled air enter the auditorium under the seats, Carrier’s installation brought in chilled air overhead at low velocity and let it settled as a cooled blanket over the auditorium. The air was then extracted through grilles under the seats. This downward distribution arrangement gave the preferred “cool-head/warm feet” stratification and became widely adopted subsequently. Carrier later went to invent the smaller and cheaper centrifugal compressor that used a new refrigerant. The new space-saving compressor was installed at new theaters that became so successful that Carrier went on to install air-conditioning systems for more than 300 theaters between 1925 and 1930.
So many movie theaters installed air-conditioning that they were indelibly linked with cool comfort. Air-conditioning was an important part of the total entertainment experience for the patrons of movie theaters, especially during the hot summer months. Marsha Ackermann noted that “over-cooled movie palace demonstrated both its pleasurable novelty and conspicuous modernity” (Ackermann 2002, 49). At around the same time, air-conditioning was also introduced in other spaces of consumption, such as the Departmental Stores.
Beyond certain industrial spaces of production and commercial spaces of consumption, air-conditioning was not as rapidly adopted. For office buildings, the lag could be attributed to the depressed economic conditions in the North America during the 1930s. The first fully air-conditioned office block is the Milam Building in San Antonio, which was completed in 1928. The architect was George Willis and the engineer, M. L. Driver. Despite its conventional exterior, the building was among the first concrete-framed skyscrapers. A small air-conditioning plant, located between the elevators and the toilets, was provided for every two office floors. The conditioned air was distributed in the space above the ceiling of the central corridors, with the corridors serving as return ducts.
The Philadelphia Savings Fund Society (PSFS) Building, 1932, designed by Howe and Lescaze is widely regarded as the first International Style skyscraper in North America. Besides pioneering the modern skyscraper form of externalized structures and articulated service tower, the PSFS building also had an innovative air-conditioning system installed by Carrier. The second fully air-conditioned office tower in the North America after the Milam Building, the PSFS building had an intermediate mechanical plant installed on the 20th floor, in addition to the plant at the basement. This reduced the size of the vertical ducts for distributing the conditioned air for the typical office floors from the 6th to the 32nd floors. From the vertical ducts, conditioned air was mixed with return air at each floor by small booster fans and distributed horizontally through horizontal ducts furred to look like a false beam.
Space saving air-conditioning ductwork was regarded as an important consideration because it minimized the loss of rentable square footage taken up by services. The space-saving innovations at PSFS foretell the solution that would subsequently be widely adopted in most office buildings. The solution by Carrier and ultimately other companies was to distribute conditioned air at high velocity through small diameter ducts and then heat or cool it at the point of delivery under the windows of the offices. That was the basis of Carrier’s renown Conduit Weathermaster system that we shall see in the post-war examples.
As noted earlier, Wolff installed air-conditioning systems for the homes of the superrich clients. There were also a few other residential installations but in general, air-conditioning was too complex and expensive for most households. Perhaps these were the reasons air-conditioning companies decided to produce mechanically cooled furniture, particularly beds, in the 1920s and 1930s. These had smaller spaces to cool and were thus more affordable. Nevertheless, they remained novelties that were not widely embraced by the consumers.
The early air-conditioning systems were complex assembly of parts and components manufactured by various companies. These systems were specially customized by engineers, such as those from the Carrier Engineering Corporation, for particular needs, uses and sites. Nobody was manufacturing or offering to sell a “complete installation as a pre-assembled package” (Banham 1984, 183). In other words, there wasn’t an air-conditioning unit that the layperson could identify as a commodity that (s)he could buy and install at home. Companies like Carrier, Chrysler and General Electric began to manufacture and sell room coolers for homes in the 1920s and 1930s but these were expensive and bulky units that had to be serviced by a refrigeration plant somewhere else. With miniaturization and other improvements, manufacturers began to produce the packaged air-conditioner – a simple, relatively small and self-contained unit that could be easily installed. It could be installed in a hole in the wall or a window, and only connected to an electrical outlet in order to operate. The packaged air-conditioning unit was central to the spread of domestic air-conditioning in the Post-World-War-II years.