The earliest home air cooling in Texas was practiced by the Mexican and Spanish population. At an early date Spanish Americans constructed adobe houses with thick masonry walls with a door or a closable opening in each of the four walls. At night the opened doors and openings permitted an all-night flow of air through the rooms. This lowered the temperature of the entire adobe wall. All openings were closed from sunup until sundown. The owner thus captured a mass of cool air in his home that lasted until siesta time, after the midday meal. During the day, the semitropical sun would heat up the outer walls by direct radiation. For the night sleeping hours, while the house was cooling for the next day, the adobe inhabitant and his family sometimes slept out-of-doors, where they could obtain the benefit of natural night cooling. The Spanish-speaking people learned this practice from African and Asiatic Arabs who had learned to employ the existing forces of nature to keep cool. From Spain this practice entered Mexico and then Texas. The early White settlers in the state also built their homes so that they could be cooled by this system of cross-ventilation.
Well water was also introduced as an air-cooling medium at an early date. The water was pumped from the well to fan radiators installed in the space to be cooled. Unless the water was pumped for other uses subsequent to its application as a coolant, this was not an economical procedure in Texas since the well water was usually 62° to 72 F and thus had little cooling potential.
In the dairy regions of Central Texas, nineteenth-century German farmers adopted evaporative cooling. This system, which was practiced extensively in Central and West Texas, was originated for milk cooling. The evening milk was placed in metal cans; fans blew air through wetted blankets covering the cans. This air took on "wet bulb" temperatures and cooled the milk to 70° or 75° F. This system was easily modified for home cooling, as is evident today in the wide range of evaporative coolers ranging from the desert variety to the sophisticated designs used in large homes, commercial structures, and government buildings. During this same period the cities in low elevations in eastern North Texas experimented with every type of fan, with ice and dry ice, and with evaporative and sky-cooling devices to combat the summer heat waves.
Manufacturing of cooling devices began in Texas cities as early as 1870 and provided the beginning of a new type of industry. Air cooling with commercial ice dates back to approximately 1910, when ice could be purchased for as little as four dollars a ton. At first the 300-pound blocks of ice were placed in a vault through which a fan blew air into an outlet duct and thence to the space to be cooled. By 1920 the ice had been placed in an enclosed pool and the ice water circulated to fan radiators in order to cool rooms, auditoriums, and restaurants. The First Baptist churches of Dallas and Austin and the Highland Park Methodist Church were ice-water cooled for many years. The first refrigerated air-cooled building in the Houston area was the Rice Hotel cafeteria, air-conditioned in 1922. The Milam building in San Antonio, which opened in 1928, was the first air-conditioned high-rise office building in the country.
By 1940 Texas had become a national manufacturing center for air-cooling machines and inventions, which ranged from lowly desert coolers to the most sophisticated forms of evaporative coolers and reversed cycle refrigerators, as well as heaters for winter heating and summer refrigerated air cooling. The latter system was designed into one machine, usually called the "heat pump." Also in the 1940s the air-conditioning industry began to include units for automobiles. By the 1950s Dallas had become a major center for the manufacture of car air conditioners. In the early 1960s Don Dixon of San Antonio broadened the potential market for the industry by inventing a unit to fit Volkswagens (cars previously considered "uncoolable"). By the 1960s air-conditioning was a multi-million-dollar industry, with manufacturing and retail establishments accounting for more than 240 businesses in the state. By the 1990s the Texas Air Conditioning Contractors Association had licensed about 8,000 contractors.
Environmental questions arose in the 1980s concerning the hypothetical deleterious effect of the chlorofluorocarbons used in air-conditioning systems. Passage of the Clean Air Act by the United States Congress in 1992 gave the Environmental Protection Agency the power to require that refrigerants be recovered and recycled. The cost of such procedures prompted the air-conditioning industry to make plans to phase out freon-based units and replace them with supposedly less harmful systems. See also REFRIGERATION.