How air conditioning shaped modern architecture—and changed our climate

During a conversation with the New Yorker, a window washer who worked on the Empire State Building says that some of his toughest moments have been cleaning the trash that tenants toss out the windows. In his many years working on the Depression-era skyscraper, he’s wiped numerous half-empty coffee cups off window panes, and even scraped 20 gallons of strawberry preserves from the building’s facade. Tossed out in the winter, it stubbornly clung to the outside of the skyscraper.

Cracking a window open in a skyscraper seems like a quirk, especially today, when hermetically sealed steel-and-glass giants offer the promise of climate-controlled comfort. But ever since Chicago’s Home Insurance Building, considered one of the first skyscrapers, opened in 1884, the challenge of airflow, ventilation, and keeping tenants cool has been an important engineering consideration shaping modern architecture.

The great commercial buildings of the modern era owe their existence, in many ways, to air conditioning, an invention with a decidedly mixed legacy.

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Air conditioning enabled our great modernist buildings to rise, but it’s also fueled today’s energy and environmental crisis. AC helped create a new building typology, one that environmentally conscious architects and designers are trying to move beyond with new designs and passive-cooling techniques.

“Modern buildings cannot survive unless hard-wired to a life-support machine,” says University of Cambridge professor Alan Short. “Yet this fetish for glass, steel, and air-conditioned skyscrapers continues; they are symbols of status around the world on an increasingly vast scale.”

Classical solutions to an age-old problem

Early skyscraper design drew from classical architectural references to help shade, cool, and circulate air. Classical towers in cities such as Chicago and New York all take their shape, in part, from the need to create a workable environment before the advent of AC.

Like the vernacular buildings that formed our early metropolises, the first skyscrapers were created with ventilation and airflow in mind. Many of the same techniques used on more earth-bound structures were simply adapted and scaled up as these new colossuses, girded by steel skeletons, arose in the commercial districts of New York and Chicago.

High ceilings, operable windows, and extensive perimeter exposure helped to encourage ventilation and air flow. In Chicago, early towers were designed with central open courts and light wells; some, like the famous brick Monadnock Building, a proto-skyscraper, were designed with a long, thin profile in mind, while other structures suggested letters when viewed from above, shaped like a “C” or an “E.” These shapes ensured daylight and cross-ventilation were available everywhere.

Standing at the corner of Randolph and State streets, the Masonic Temple, then the world’s tallest commercial building, proudly proclaimed its dominance of the skyline. Designed by John Wellborn Root of the firm Burnham & Root, the muscular, 21-story giant briefly towered above all others in the city that birthed the skyscraper. But its height wasn’t the only feature that made it exceptional.

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The secretive Masons used many of the uppermost floors for their own rites and rituals. A glass-covered roof garden, a steam-heated space decorated with oak panels, was available for private parties and galas. But for the most part, guests entered through the gilded lobby, took one of the 14-passenger elevators to their floor, and got about their business. They’d enter their office, designed with high ceilings to help capture the natural daylight, and crack open a window to provide some ventilation.

The early architects of these plans drew influences from classical architecture, much like their facades took design cues from historical references. One of the big names of Chicago architecture at the time, Louis Sullivan, designed a building in St. Louis, the Wainwright Building, meant to mimic the layout of the Uffizi, a Florence, Italy, administrative building constructed in the 17th century. Chicago skyscrapers even had specific window designs, with a large, fixed pane surrounded by smaller sash windows that could be opened for ventilation.

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The new class of white-collar workers who occupied these upper-level offices suffered through humid summers not just because they didn’t know any better, but because Victorian social mores didn’t place much stock in personal comfort. In fact, the adoption of mechanical ventilation systems, which were invented by Benjamin Franklin Sturtevant in the 1860s and became more common in taller buildings towards the end of the 19th century, was due in large part to the problems of heat and light—coal- and gas-powered lamps and heaters quickly filled rooms with toxic smoke—and the belief that poor health was caused by miasma, or dirty air.

Still, at the time, ventilation was less about a comforting breeze and more about sanitation—removing humid, fetid air from crowded workshops and workspaces. By the mid-1890s, designers and architects in New York needed to file their building plans with the Bureau of Light and Ventilation. The 21-story American Surety Building in New York, built in 1896, included a ventilation system, but only for the lower seven floors. Workers on these levels couldn’t open their windows due to the dirt, muck, and grime of the city streets.

Roof gardens and ice pipes

Many early attempts at indoor cooling took place in theaters, according to Cool: How Air Conditioning Changed Everything by Salvatore Basile, which could become unbearably stuffy during late-summer performances. Pumping air cooled by ice, or granting access to roof gardens, occasionally helped keep theatergoers from being overwhelmed by stale, humid air, but most failed, or made a barely noticeable difference.

That didn’t stop roof gardens from becoming a big part of the entertainment circuit. In New York City, the Madison Square roof garden could accommodate 4,000 people. Not to be outdone, the Paradise Theater roof garden featured a faux village with a windmill, waterfall, and two live cows with milkmaids. While they couldn’t deliver true refreshment, they could offer at least the illusion of cool. The nearby Victoria Theater actually heated the elevator that took patrons to the roof, so they would gain the illusion of relief.

Before reliable technology was invented, cooling was a much more complicated affair, though that didn’t stop entrepreneurs from trying. According to Basile, their attempts usually involved relatively brute means of mechanically circulating cold air. The Colorado Automatic Refrigerating Company set up a “pipe line refrigeration” system in downtown Denver, running two miles of underground pipes through the business district and offering a hookup to local building owners looking for ice-cooled air. In New York, the Stock Exchange opened a comfort cooling system, a forced ventilation system, the largest in the country at the time.

A few early pioneers tried their hand at other primitive forms of mechanical cooling. Perhaps the first was the Armour Building in Kansas City. Built in 1900, the packing plant, designed by William Rose, the city’s one-time mayor, featured a spraying room, which sent air through a misting system that “washed” it, cooling it just a few degrees.

Willis Carrier’s invention of artificial refrigeration in Brooklyn in 1902 would prove to be a turning point, but not immediately. He stumbled upon the technology while trying to create a machine that would dry out printing rooms so ink wouldn’t smear on the presses in humid temperatures. Carrier’s machine “dried” air by passing it through water to create fog, which had the by-product of cooling the surrounding space.

Fittingly, the marvel had a wide range of industrial uses, and Carrier focused on that market at the beginning. While Carrier would eventually push for residential applications, also targeting the new movie theater market, the adoption of residential and office air conditioning was relatively slow.

The first air-conditioned buildings

In 1913, Carrier had his first residential installation, the Minneapolis mansion of Charles G. Gates. A rich man so free with his inherited wealth that he was nicknamed “Spend a Million,” Gates wanted the best of the best for his new 38,000-square-foot home, including a pipe organ and gold doorknobs. He purchased a Carrier unit designed for a small factory, according to Basile, but he sadly wasn’t able to enjoy his gilded glory; he died during a hunting accident before the home was finished (his wife would live there only briefly, and the building was sold and finally demolished in 1933).

Frank Lloyd Wright also made an early attempt at air conditioning with the Larkin Administration Building in Buffalo. A breakout project for the young architect, the new corporate headquarters for a regional soap company showed his knack for making people “comfortable” in his own particular way. The skylight atriums added to allow in natural light just made the office uncomfortably warm, and the awkward, custom-designed desks and chairs he created were nicknamed “suicide chairs” for their propensity to tip over. Architectural Record called it a “monster of awkwardness.”

Since the office was adjacent to the company’s factory, Wright also decided to seal the structure from the clouds of dirty exhaust. An air-circulation and cooling system, utilizing a washing system similar to the Armour Building, was installed, but like the Kansas City design, didn’t make much of a difference, especially with all the solar gain that came from Wright’s skylights. Proper air-conditioning equipment would be added years later, but that didn’t stop Wright from rewriting history to suit his purposes. He would later repeatedly claim this was the first air-conditioned building in existence.

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While building technology improved and grander, taller structures began to dominate skylines, cooling technology didn’t change much in the prewar years, or add much to construction. Even skyscrapers such as the Chrysler and Empire State buildings relied partially on natural ventilation to keep occupants cool, and in Chicago, the palazzo style of tall towers remained. It would require bigger, postwar leaps in construction and design to truly change how buildings were designed.

Life behind a glass wall

The postwar housing shortage created a cottage industry of dreamy new home designs, offering comfort and modern conveniences to Americans clamoring for their own home and a slice of the suburban dream. Some, like Buckminster Fuller’s Dymaxion model, a $6,500 passive house prototype that utilized “thermo-ventilation,” may have been technically advanced, but were aesthetically a bit of a dud. Americans wanted style, and the emerging school of California architecture delivered.

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Most powerfully represented in the popular imagination by the Case Study House program started by Art & Architecture magazine in 1945, the California modern home was an aspiring homeowner’s dream, an effortless, breezy layout, utilizing new construction techniques to promise something distinctly modern. Inspired by the stark, angular International school of architecture, these homes, mostly flat-roofed, single-story construction with glass walls and overhanging eaves, looked cool.

But for those not living in the supremely advantageous climate of California, they also offered false hope. Relying primarily on cross-ventilation to keep cool, and requiring little to no insulation, these homes just didn’t work in other regions of the country, especially those prone to muggy, humid summers.

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The (im)perfect example of this would be the Farnsworth House, an aesthetic marvel that proved the impracticality of glass house living. Designed by Mies van der Rohe, perhaps the figurehead of International Style design in the United States, the glass box floating above a forested glen in Plano, Illinois, was a beauty. It also baked in the mid-day sun, due to a lack of shading, and at night, the light-up cube became a beacon for bugs. The owner, Dr. Edith Farnsworth, complained about the home, eventually suing van der Rohe and even hiring a contractor to create custom brass screens to ward off insects.

Building the sealed box

While the midcentury aesthetic may have been sleek and modern, it was also terribly uncomfortable without the ability to create an artificial environment inside. But right as the modern, International Style building became popular, air conditioning and modern engineering suddenly made it possible to design glass-and-steel structures with controlled temperatures. Lewis Mumford once used the phrase “facade demanded by air conditioning” to describe a modern office building; that perfectly describes the relationship between artificial cooling and the modern glass commercial building.

Some early experiments that paved the way; the PSFS Building in Philadelphia, a modernist gem designed by William Lescaze and George Howe and built in 1932, is considered the first International Style high-rise, and also utilized air conditioning. Portland’s Equitable Savings and Loans structure, constructed with an aluminum and glass shell, was completely air-conditioned. But it was two blockbusters in New York City, according to Basile, that popularized the glass box style of commercial structures that dominated the last half of the 20th century.

The first, the UN Secretariat Building, could actually be seen as much as a cautionary tale as a groundbreaker. The high-profile commission, designed by modernist master Le Corbusier in 1948, was to be an evolution of his own past buildings, a striking—and smart—high-rise that utilized sunbreakers, or brise-soleil, to cut down on heat gain, as well as operable windows. Corbu had tried to seal a glass structure when he designed his Cite de Refuge housing complex in France in 1933, which ended up creating a heat trap in the summer. He didn’t want to repeat his mistake.

“My strong belief is that it is senseless to build in New York City, where the climate is terrible in summer, large areas of glass that aren’t equipped with brise-soleils,” he said. “I say this is dangerous, very seriously dangerous.”

Sadly for Corbu, the UN didn’t listen. The 39-story building, on the east side of Midtown Manhattan, was coated in Thermopane heat-absorbing glass. Despite operable windows, and the installation of 4,000 Carrier units in the building, the west-facing offices were roasted with constant sun exposure. Shortly after moving in, the staff installed blinds, which Corbu cursed as covering the building in a “morguish light.” While the rectangular structure presented a sleek, modern profile, the heat issue was a huge problem (the building now costs nearly $10 million annually to heat and cool). Critic Henry-Russell Hitchcock went so far as to say it showed why glass walls shouldn’t be used for skyscrapers.

But just a few years later, a new project across town totally changed the conversation about International Style office towers. It presented a clean, pristine vision of cleanliness and cool, and just happened to be funded by a soap company.

Finally, a cool modern office

The Lever Brothers company wanted a new headquarters in New York City, and president Charles Luckman wanted the company’s new home to make a statement. A former employee for SC Johnson Company, which famously hired Frank Lloyd Wright to design its futuristic headquarters and research tower in Racine, Wisconsin, Luckman knew how a new building could play in the press. He decided that he wanted something au courant, and that reinforced the company’s values.

The resulting glass box design, 1952’s Lever House, became a sensation. Designed by Gordon Bunschaft of Skidmore, Owings & Merrill, the 24-story, sea-colored glass box presented a total environment for work; employees could enter through the large ground-level plaza or underground parking garage, eat in the cafeteria, and work in an office kept cool and clean by air conditioning and mechanical ventilation. The first glass curtain wall building, it was literally a revelation—passersby could glance near the edges of the building and see out another glass wall around the corner. Employees “didn’t have to breathe the same air as New Yorkers,” and the hermetically sealed exterior cut down on heating, cooling, and cleaning costs because less city dirt and dust made its way through open windows.

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Luckman didn’t miss a chance for self-promotion, either. The massive walls of sealed glass couldn’t be cleaned from the inside, so the company draped a $50,000 “window-washing gondola” from the roof, a publicity stunt that used Lever-brand Surf soap to scrub the windows clean every six days.

Beyond creating a new style for skyscrapers, the Lever House became an icon that truly made the company mainstream. The thin tower, set on a wide base, was also a quirk of New York City zoning laws that restricted buildings from taking up the entire lot (hence the setbacks often seen on older towers). But with an air-conditioned interior and electric lights, suddenly tall glass towers could take up the entire lot. Gone was the need to create atriums or light wells; windowless deep space could fill in those gaps and make a commercial development more profitable.

The Lever House represented a tipping point. Soon, other buildings in New York City, including the Empire State Building and the Woolworth Building, felt the need to add air conditioning. Carrier noticed that as soon as 20 percent of the buildings in a given market added AC, others felt pressure to adapt or fall behind. Priorities changed: Whereas buildings of the past focused on grand lobbies, with workplaces that were spartan areas for getting things done, in modern buildings, comfortable settings altered available layouts.

Since the availability of air conditioning meant workers didn’t need to sit near a window, offices could suddenly have larger floorplates, encouraging collaboration and denser construction. Numerous building typologies adapted to this sudden freedom; look at how the Houston Astrodome, an 18-story air-conditioned baseball park in Houston, transformed the concept of a traditional baseball stadium.

Blown over: The backlash and environmental costs of keeping cool

The confluence of new technology and expanding cities has created scores of marvelous skyscrapers, from the Seagram Building to the Willis Tower. But the proliferation of air-conditioned space, and the types of buildings that have flourished under this new technology, has shown the gleaming, modern world it creates is far from utopian.

Air-conditioned construction quickly changed the urban landscape. The adoption of the “windowless wall” created the fluorescent-lit, dull and dim office spaces many workers abhor. Malls became a dominant part of the late-20th-century built environment. Life magazine didn’t mince words when it railed against “unimaginative boxes of air-conditioned office space, which increasingly dominated U.S. urban architecture” (the article was titled “How to Make Any City Ugly”). Unhealthy air quality inside closed-off buildings also was cited for major health implications.

But the most damaging part of this shift has been the cost, in energy and carbon emissions, of our cool new world. By 2014, 87 percent of U.S. homes had some form of air conditioning. The cooling of buildings in the United States contributes to half a billion metric tons of carbon dioxide emissions every year. We consume more energy for residential air conditioning than all other countries combined, although, with other countries such as China and India in pursuit of glass-walled visions of modernity, that is going to change, and not in a good way. Due in large part to indoor climate control, buildings utilize half of total U.S. energy consumption.

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Artificial cooling has become such an energy hog, and so detrimental to efforts to fight climate change, that skyscraper design has begun to shift back toward the vernacular techniques used in the pioneering buildings of the late 19th century. Frankfurt’s Commerzbank Tower, a Foster & Partner’s project that opened in 1997, was considered one of the most eco-friendly towers at a time before LEED standards, utilizing daylighting and the “new” concept of openable windows. The Queen’s Building at De Montfort University in Leicester, from 1995, is naturally ventilated and passively cooled. Others architects are playing with ideas of bioclimactic architecture, or utilizing plants as natural cooling agents.

Air conditioning promised a cooler, more modern environment indoors. But unless architects and designers continue to develop more green, efficient ways to keep our buildings cool, it will be increasingly difficult to escape the warming environment outside.