In 2023, Jeep rolled out a new edition of its popular four-wheel-drive SUV. For the first time since the company introduced the car in 1986, air conditioning wasn’t an option, it was a must. This appears to be the end of an era: “The last car in the U.S. without standard air conditioning,” read the headline of an article in the automotive press, “finally gives up the fight against refrigerant.”
This summer, all across the torrid globe, air conditioning was a necessity for billions of people, though less than a third of households have it. In the Northeast and Mid-Atlantic, it offered defense against not just the heat but also the eerie orange smoke from Canadian wildfires exacerbated by climate change. In Phoenix, where the temperature rose above 110 degrees for weeks on end, temporary cooling centers were a lifesaver for homeless people, though hundreds of heat-related deaths were confirmed or suspected throughout the metropolitan area. In Europe, where air conditioning is evolving from an eccentric, American-style indulgence to a standard amenity, AC offered a critical defense against a heat wave so powerful and persistent that the Europeans gave the high-pressure system causing it a name, “Cerberus,” after the mythological three-headed hellhound who guards the gates of Hades. Zehnder Comfoair Q350 Manual
As temperature records were broken across the planet this summer, you could sense something shift in our relationship to air conditioning. Billions of people in the Global South and other hot zones still live without household air conditioning. And the cost of remedying that is staggering. But it isn’t just the financial challenge of manufacturing and distributing more cooling systems. The environmental costs are terrifying, too. Making internal spaces cooler for humans means making external environments hotter for all living things, with more industrial production, shipping and energy consumption, all of which contribute to the buildup of greenhouse gases.
But even in places where air conditioning has been standard for decades, including the United States (where, according to the International Energy Agency, more than 90 percent of households have artificial cooling), how the technology intersects with fundamental feelings about safety and well-being is changing. Older Americans, who can still recall the preternatural cool of movie theaters as a rare escape from the tedious heat of summer, must now consider the physical stress of hot weather as a significant determinant of mortality.
Summers now last longer — well past the autumnal equinox in many places — and as hot weather spreads to more clement regions, schools must consider the effects on learning without air conditioning. A 2020 study predicted that if temperatures in the contiguous United States rise as predicted, by 2050 students will learn on average 10 percent less each year. The effects are cumulative, and students without AC in their schools, who often live in cooler regions of the country, are the most vulnerable.
The heat index measures temperature and humidity to help assess how hot it feels outside. Days with index values above 65 degrees typically demand AC. In the early 1980s, the continental United States required AC for 61 days, or about 66 percent of July to September. Now about 71 percent of summer days requires AC. By 2060, the number of AC-required summer days is projected to rise even more, to 87 percent.
More fundamentally, air conditioning is evolving rapidly from an appliance that adds comfort and convenience to an ever-present life-support system. It’s no longer mentally associated with things such as toasters, refrigerators and televisions but instead with those often-invisible systems that we take for granted until they fail, such as the electrical grid or medical implants, pharmaceuticals and the blood supply.
It’s possible to see a future in which we are dependent on the perfect, continuous performance of air conditioning the way many people are dependent on lifesaving drugs, planes are dependent on air traffic control, and a colony on the moon or Mars would be dependent on perpetual sources of oxygen and water. It is a technology so deeply embedded in our daily lives, and so increasingly important to our survival, that when we think of it, it is not with pleasure, as a luxury, or with pride, as an exemplar of our technical ingenuity. Rather, it reminds us of our frailty. As the danger zone for excess heat creeps into once clement zones, the air conditioner joins the furnace as an essential system for ever more people.
We are now at about the century mark since air conditioning began its conquest of America — in movie theaters in the 1920s; in trains, hotels and other public places in the 1930s; and with astonishing speed and reach, in private homes and suburbia since the 1950s. The history is longer, messier and more complicated than that shorthand, but AC’s basic trajectory has been from a curiosity and luxury to an amenity to a necessity. It has changed how we live and where we live, and reconfigured our cities, houses, politics and identity. And now it is bound up with our hope for survival as a species.
How air conditioning arrived in U.S. households
1917 : Two theaters, the New Empire
Theater in Alabama and the Chicago
Central Park Theater, are among the
1928 : The first “tall” office building to
be fully air-conditioned is the Milam
1938 : 22 million homes are wired for
electricity in the U.S., with less than a
quarter of 1 percent of them having AC.
1955 : All new federal buildings are
determined to need AC if outside
for sustained periods. This moves the
heat line from the D.C. area up into
10% of all U.S. households have AC.*
1959 : The U.S. Weather Bureau
creates a “Discomfort Index”
as a climate guide to cities.
The name is replaced by the
direct deaths and as many
*Note: Household AC data available from 1957 to
Sources: EIA, Comin and Hobijn (2004) and others,
HANNA ZAKHARENKO/THE WASHINGTON POST
How air conditioning arrived in U.S. households
1917 : Two theaters, the New Empire
Theater in Alabama and the Chicago
Central Park Theater, are among the
1928 : The first “tall” office building to
be fully air-conditioned is the Milam
1938 : 22 million homes are wired for
electricity in the U.S., with less than a
quarter of 1 percent of them having AC.
1955 : All new federal buildings are
determined to need AC if outside
for sustained periods. This moves the
heat line from the D.C. area up into
10% of all U.S. households have AC.*
1959 : The U.S. Weather Bureau
creates a “Discomfort Index”
as a climate guide to cities.
The name is replaced by the
more than half of its
1980 : A heat wave of unusual
and East. It caused over 1,200
direct deaths and as many
*Note: Household AC data available from 1957 to 2020
Sources: EIA, Comin and Hobijn (2004) and others, Our World in Data
HANNA ZAKHARENKO/THE WASHINGTON POST
How air conditioning arrived in U.S. households
1917 : Two theaters, the New Empire Theater
in Alabama and the Chicago Central Park
Theater, are among the earliest documented
to include refrigerated air conditioning.
1928 : The first “tall” office building to be
fully air-conditioned is the Milam Building
1934 : Detroit’s Statler Hotel extends the
use of AC into individual guest rooms.
1938 : 22 million homes are wired for
electricity in the U.S., with less than a
quarter of 1 percent of them having AC.
1952 : AC is incorporated into post-war
tract housing, changing the design of
roofs, windows, attics and other features.
1955 : All new federal buildings are determined to
need AC if outside temperatures are above 80
degrees for sustained periods. This moves the heat
line from the D.C. area up into northern states.
1959 : The U.S. Weather Bureau creates
a “Discomfort Index” as a climate guide
to cities. The name, unpopular with civic
boosters in hot states, is replaced
1965 : The Houston Astrodome opens, the
first air-conditioned domed stadium in the
state to have more than
half of its homes and
Carter declares a national energy
to mandate that AC be set no
lower than 78 degrees in all
Midwest and East. It caused
over 1,200 direct deaths and as
from heat stress. It is still considered
one of the most significant heat
waves in U.S. history.
*Note: Household AC data available from 1957 to 2020
Sources: EIA, Comin and Hobijn (2004) and others, Our World in Data
HANNA ZAKHARENKO/THE WASHINGTON POST
To comprehend the impact of air conditioning on this country, one has to entertain a dystopian thought experiment: Where would we be without it? Much of the South would be poorer than it is now, and isolated, with high mortality rates and lower educational achievement. There would be no skyscrapers in Atlanta, no high-rise apartment buildings in Dallas and Houston. In our hottest states, including the Sun Belt, public institutions, including universities, libraries and entertainment venues, would be fewer and more minimally developed. Entertainment would still be seasonal. City theaters would close as temperatures rise, and music, drama and the movies would migrate outdoors. Many of the products we take for granted, including textiles and foodstuffs that rely on atmospheric controls or refrigeration, would be of far inferior quality and much more expensive.
Architecture would look very different, at least for those who could afford such niceties as higher ceilings, wider eaves and more sharply pitched roofs (all of which can passively cool a house). The picture window — a source not just of light but also of heat, and which can’t be opened for ventilation — would not be a key element of suburban design. The ranch house, with thin walls and low ceilings, laid out in relentless grids across the Sun Belt since the 1950s and immortalized in the haunting photographs of Robert Adams, wouldn’t define the vernacular architecture of America.
And the many millions of people who live in those types of houses would live elsewhere, in cooler states. The net migration from the South, which continued from the Civil War until around 1964 (when air conditioning was well established in the country’s hottest states), would be ongoing. In a 2004 book, the political scientist Nelson Polsby argued that air conditioning increased political polarization, with an influx of Northern Republicans into the South, and a resorting of the Democrats into a northern, more progressive, urban party without a conservative Dixiecrat wing.
It may have also changed the way women conceive of feminism and liberation from patriarchy, from a model based on independence and working outside the home in the early 20th century to one structured around the supposed leisure offered by the modern, air-conditioned tract home in the middle of the century. Gore Vidal once argued that we would have been a more free, more civilized nation had air conditioning not been introduced early into Washington’s federal buildings, including the U.S. Capitol, which induced politicians to linger longer and make mischief in the nation’s capital.
“I date the end of the old republic and the birth of the empire to the invention, in the late Thirties, of air conditioning,” Vidal said in 1982, with his usual sweep and approximate sense of the facts. AC was invented earlier, but it did arrive at the Capitol much sooner than other parts of the country, which contributed to a sense that politicians were enjoying a luxury not available to most of their constituents.
The age of air conditioning is extraordinarily well documented, in newspapers, advertising, industry journals, census data and popular literature, which gives texture to the technology’s evolution. Before air conditioning, chocolate was often produced in basement workshops, where temperatures were lower. Many bakeries in Chicago were subterranean, too, and the dark, damp working conditions were considered a vector of disease. Hotels in the South routinely included a dollar surcharge for air-conditioned rooms. With the advent of cooling in theaters, patrons — especially women, whose legs were more exposed to cold updrafts — would use newspapers to keep their lower extremities warm. Heat-related deaths appeared in media accounts as a routine, macabre daily fact of life.
These quotidian details were recorded but little remembered, rather like the way some people in hot places today keep oven mitts in their cars to temper the heat of the steering wheel — a fact astonishing to everyone but those for whom it is lived reality.
Less tangible are the poetic details of life before AC that are embedded in art and literature. Staying cool in hot weather was often a social experience, a collective lethargy that brought one closer to family and community. James Agee’s prose poem “Knoxville: Summer of 1915” begins, “It has become that time of evening/ When people sit on their porches,” and then proceeds to a litany of all the things one used to hear (“The dry and exalted noise of the locusts”) before closed windows and the hum of the fan and compressor shut out the aural richness of the world.
Author and artist Faith Ringgold created narrative quilts and a children’s book about summer nights on “tar beach”— the rooftop of her New York apartment building where her family would escape the heat. Tar beach was a place of fantasy where, surrounded by the beauty of the city and the care of her family, the young artist imagined that she owned “all that I could see.”
As you dig into the history of AC, it begins to take on the dimensions of some vast conspiracy, like the destruction of streetcar lines to make us car dependent, or the marketing of tobacco or opiates to encumber us with mass addiction. It’s tempting to inflate the importance of air conditioning into a unified theory of everything. A popular history of the technology is subtitled: “How Air Conditioning Changed Everything.” But nothing is ever that simple.
In fact, air conditioning was just one part of a larger nexus of technology and capitalism that reshaped America. It arrived slowly and imperfectly and was adopted in fits and starts, first in industry, where textiles, tobacco and printing were particularly subject to variations in humidity. The unit of a ton, still used to determine the size of an air-conditioning system, comes from the heat transfer of a ton of ice over a 24-hour period — a vestigial reminder of a basic method of cooling in the 19th century. Throughout the history of mechanical ventilation and “comfort cooling,” there was resistance to innovation, with a vocal and determined “open air” movement that opposed mechanical ventilation in public schools.
Without marketing, advertising, subsidies and alliances among major industries, air conditioning might never have become the essential, invisible, gently grinding backdrop to almost every indoor space in America today. And thus, we have an unknowable chicken-or-egg philosophical question: If capitalism hadn’t sold us on the necessity of air conditioning and other modern innovations, might we not be so entirely dependent on air conditioning today? If we hadn’t built a world around and dependent on systems such as AC, might the world be a lot cooler?
Andrea Vesentini, a scholar based in Venice, has studied the imagery and advertising used to sell air conditioning to America in the middle of the last century. The advertisements he has culled from magazines and popular journals depict a dramatic contrast between interior and exterior space, and an emerging inside-outside dichotomy that had strong class overtones. Elegantly dressed people lounged in artificially chilled modernist spaces, while workers dressed for more rugged activity suffered outside in the blazing heat of the day. Hot and cold, inside and outside, were racially coded, too. In a 1949 Carrier ad that ran in the Saturday Evening Post, a man lies sleeping under a sombrero outside, while the text appeals to the sensibilities of entrepreneurs and business executives: “Temperature 102º — Production 0.”
Air conditioning was part of a suite of modernist gadgetry that would transform the home into a place of leisure. Dust wouldn’t creep in through open windows. Healthy, perfectly manufactured air would be available at the touch of a button. One 1954 survey cited in Vesentini’s book “Indoor America: The Interior Landscape of Postwar Suburbia” claims that residential climate control allowed housewives to expand their hobbies from four to nine.
Throughout this mid-century period, manufacturers, power companies, home builders and developers were working in concert to embed air conditioning in American life, appealing to a broadly libertarian ideal of the home as a safe, independent, self-contained space apart from the larger messiness of American democracy.
Utilities promoted electrical consumption, which meant increased profits. In the late 1950s, General Electric spokesman Ronald Reagan promoted the “Gold Medallion Home” program, which offered homeowners a bronze plaque for stuffing their houses with electrical systems and appliances. Air conditioning helped spur self-reinforcing cycles of development: Developers offset the cost of central air by building cheaper, flimsier houses, which performed poorly in heat, necessitating artificial cooling, while power companies developed greater capacity that attracted industry and workers, which in turn required more housing and electricity.
Slowly, decade by decade, the fantasy and spectacle of air conditioning faded, and we began to take it for granted. When it was first widely introduced into movie theaters in the 1920s, air conditioning was an integral part of a larger program of escape and imagination. Theater architects indulged every whim of excess, mixing Egyptian, classical and baroque gestures into wild excesses of ornament, often with the ceiling representing an open nighttime sky — a visual memory of cool evenings under the stars.
The movie itself, many theater moguls acknowledged, was secondary to the larger experience. Indeed, Hollywood schlock may be yet one more element of American cultural life linked to artificial cooling. Theaters needed product to entertain people who came mainly for the cool air. Marcus Loew, whose theater chain was eventually subsumed in AMC Theatres, once said, “We sell tickets to theaters, not movies.”
When Rockefeller Center was constructed in Midtown Manhattan in the 1930s, one of its beloved public spaces — the ice-skating rink — was crowned with Paul Manship’s golden statue of Prometheus, the Titan who stole fire for the benefit of mankind. The art deco urban development itself, home to thermally sensitive radio studios and public theaters, also needed enormous air-conditioning capacity — and the ice-skating rink was a visual reminder of that small miracle of engineering. Prometheus, by extension, was seen not just as the bringer of fire but also something even more wondrous — the bringer of ice.
There is a curious resistance to Prometheus throughout the history of air conditioning and artificial cooling. Lingering Victorian social customs, which valorized an uncomplaining serenity in the face of hardship, including extreme heat, also led to resistance. From the early days of mechanical ventilation, there was suspicion that engineers were corrupting the natural order of things, weaning people away from fresh air and open windows in favor of diabolical new systems. Some social critics, including the truculent Henry Miller, associated air conditioning with everything that was artificial and false in the new American techno-utopia.
Early engineers talked about air conditioning in terms that sound odd today. They didn’t just want to cool interior space but to engineer “man-made weather.” The ambition latent in that phrase connects the technology to the larger, modernist project, which conquered darkness, defied gravity, extended life and put humans on the moon and their proxies beyond. But in the end, the engineers were prescient. They did, indeed, manufacture human-made weather — with longer summers, hotter seas, more ferocious storms, and extremes of drought and flooding. Now we face a disconcerting future, as an indoor species. Mankind made his own weather, and now he must endure it.
So we dream of a new Promethean benefaction, to rescue us from the unintended side effects of his last gift. Perhaps solar power or renewable energy will offset the environmental costs of running a globe full of air conditioning. Perhaps air conditioning can be made more efficient, with new miracle desiccants — chemicals that dry air — reducing energy consumption. Maybe the whole globe can be cooled by pumping sulfuric acid into the stratosphere, to make the planet more reflective of the sun’s energy, thus engineering human-made weather on a planetary scale.
The new dream is an uneasy one and vastly different from the old one. We seek not an escape from bad weather or occasional respite from the long hot summer. We want to live beyond or without weather, because the weather we made is killing us.
The heat index values were calculated for July to September based on temperature and dew point metrics from the National Oceanic and Atmospheric Administration for the current and historical periods (1981-2022). For the projected 2060 period, we used forecasted air temperature and specific humidity from the NASA Center for Climate Simulation to compute the same metric.
Based on 2022 research, a 65 degree heat index threshold was used to determine AC requirements. We counted any day surpassing this threshold as requiring AC and calculated for all locations annually. The heat index and threshold calculation analysis was assisted by Colin Raymond, a UCLA research scientist.
Icomfort M30 Smart Thermostat Editing by Amy Hitt and Janice Page. Design editing by Eddie Alvarez. Graphics editing by Emily Eng. Art direction and design by Carson TerBush. Illustration by Vasava Studio. Graphics by Szu Yu Chen and Hanna Zakharenko. Photo research by Moira Haney and Annaliese Nurnberg. Photo editing by Annaliese Nurnberg. Copy editing by Carey Biron.