Until the late 1920s, air was not conditioned, though it was circulated through fan blades. Thereafter, scientists developed a means for creating a cooling effect through the evaporation of chemical substances. Conditioning, or taking action to put something in a better condition, comes from a rather simple Latin word, condicere, or “to speak with.” That which was spoken between two parties became a “condition,” and came to refer to a more formal stipulation made to limit or otherwise define an agreement. From the noun “condition” in this sense came the verb (attested from 1844) “to condition,” or to bring to a desired condition. In its original sense, from the 16th century, then, a conditioner was a person who made conditions, but by the end of the 19th century, a conditioner was not a person, but rather an agent that makes things better. Some earlier uses pertain to substances used to condition the soil for planting, but the usage of conditioner really spiked in the 20th century with the advent of the two kinds of conditioner that everyone needs if they want to look and feel good on a hot summer’s day: the air conditioner and the…well, hair conditioner.

Back at the end of the 18th century, Benjamin Franklin, who seems to have invented and coined nearly everything, discovered that the evaporation of alcohol and some other substances produces a cooling effect. Over in England, Michael Farraday, better known for his work on electromagnetism, discovered that the same was true about ammonia. Other cooling methods also were considered, including the very simple process of blowing a fan over melting ice so as to distribute the cool air created through the melting process. In fact, after the assassination attempt on President James Garfield in July 1885, naval engineers tried to create a fan-based air conditioner to keep him cool. Unfortunately, Garfield died anyway. Window air conditioners, not unlike the ones many of us use today did not come into home use until the 1930s, and then only for the fabulously wealthy. In 1939, Packard put in the first automobile air conditioners.

The usage of “air conditioner” in print was on a nearly continuous upward curve through the 1980s. Some of the most intensive periods of building in the United States–the decades following World War II–coincided with the American love affair with air conditioners, such that buildings were not designed to make use of natural light and cooling mechanisms. This trend has come under fire with growing awareness of the perils of fossil fuel use. As a New York Times article last summer pointed out, generations of (particularly female) workers who come to the office in their summer wear find themselves freezing in offices cooled enough to make a man in a full suit comfortable. Architects are thinking now about how to save money and increase comfort by cooling by more natural means, particularly as some of the hottest parts of the world are becoming wealthy enough to afford air conditioners, something that could present a real energy crisis.

Hair conditioners have an even later history. People have been putting any number of oils and substances in their hair since ancient times, with the goal of softening it; what was shared among these products was an oily or creamy substance which had the effect of softening the hair and removing static electricity. Our modern conditioner dates back to a substance called Brilliantine, presented by Edouard Pinaud, a renowned parfumeur, at the 1900 Universal Exposition in Paris. It was a perfumed oil, and Pinaud claimed that it would soften men’s beards. It took until the 1950s, a period of growing middle-class prosperity in the US coupled with the emergence of teenagers with disposable income to be targeted by marketers, for “shampoo and conditioner” to become a duo as inseparable as peanut butter and jelly. The first commercial conditioners were “cream rinses,” which helped detangled the hair. By the 1970s, conditioners, which coated the hair and claimed to add shine, were becoming established, and the usage of the phrase “shampoo and conditioner,” at least in printed materials, shot up for decades before leveling off around 2005. “Dry hair loves nothing better than contact with a cream conditioner, gushed Woman’s Own in 1960.” Pert Plus, the first shampoo + conditioner, was not released until 1986.

We might say that nowadays we are strongly conditioned to demand our conditioners.