The air conditioning trap: how cold air is heating the world

The warmer it gets, the more we use air conditioning. The more we use air conditioning, the warmer it gets. Is there any way out of this trap? 

Aug. 29, 2019

n a sweltering Thursday evening in Manhattan last month, people across New York City were preparing for what meteorologists predicted would be the hottest weekend of the year. Over the past two decades, every record for peak electricity use in the city has occurred during a heatwave, as millions of people turn on their air conditioning units at the same time. And so, at the midtown headquarters of Con Edison, the company that supplies more than 10 million people in the New York area with electricity, employees were busy turning a conference room on the 19th floor into an emergency command centre.

Inside the conference room, close to 80 engineers and company executives, joined by representatives of the city’s emergency management department, monitored the status of the city power grid, directed ground crews and watched a set of dials displaying each borough’s electricity use tick upward. “It’s like the bridge in Star Trek in there,” Anthony Suozzo, a former senior system operator with the company, told me. “You’ve got all hands on deck, they’re telling Scotty to fix things, the system is running at max capacity.”

Power grids are measured by the amount of electricity that can pass through them at any one time. Con Edison’s grid, with 62 power substations and more than 130,000 miles of power lines and cables across New York City and Westchester County, can deliver 13,400MW every second. This is roughly equivalent to 18m horsepower.

On a regular day, New York City demands around 10,000MW every second; during a heatwave, that figure can exceed 13,000MW. “Do the math, whatever that gap is, is the AC,” Michael Clendenin, a company spokesman, told me. The combination of high demand and extreme temperature can cause parts of the system to overheat and fail, leading to blackouts. In 2006, equipment failure left 175,000 people in Queens without power for a week, during a heatwave that killed 40 people.

This year, by the evening of Sunday 21 July, with temperatures above 36C (97F) and demand at more than 12,000MW every second, Con Edison cut power to 50,000 customers in Brooklyn and Queens for 24 hours, afraid that parts of the nearby grid were close to collapse, which could have left hundreds of thousands of people without power for days. The state had to send in police to help residents, and Con Edison crews dispensed dry ice for people to cool their homes.

As the world gets hotter, scenes like these will become increasingly common. Buying an air conditioner is perhaps the most popular individual response to climate change, and air conditioners are almost uniquely power-hungry appliances: a small unit cooling a single room, on average, consumes more power than running four fridges, while a central unit cooling an average house uses more power than 15. “Last year in Beijing, during a heatwave, 50% of the power capacity was going to air conditioning,” says John Dulac, an analyst at the International Energy Agency (IEA). “These are ‘oh shit’ moments.”

All of these reports note the awful irony of this feedback loop: warmer temperatures lead to more air conditioning; more air conditioning leads to warmer temperatures. The problem posed by air conditioning resembles, in miniature, the problem we face in tackling the climate crisis. The solutions that we reach for most easily only bind us closer to the original problem.

The global dominance of air conditioning was not inevitable. As recently as 1990, there were only about 400m air conditioning units in the world, mostly in the US. Originally built for industrial use, air conditioning eventually came to be seen as essential, a symbol of modernity and comfort. Then air conditioning went global. Today, as with other drivers of the climate crisis, we race to find solutions – and puzzle over how we ended up so closely tied to a technology that turns out to be drowning us.

Like the aqueduct or the automobile, air conditioning is a technology that transformed the world. Lee Kuan Yew, the first prime minister of independent Singapore, called it “one of the signal inventions of history” that allowed the rapid modernisation of his tropical country. In 1998, the American academic Richard Nathan told the New York Times that, along with the “civil rights revolution”, air conditioning had been the biggest factor in changing American demography and politics over the previous three decades, enabling extensive residential development in the very hot, and very conservative, American south.

A century ago, few would have predicted this. For the first 50 years of its existence, air conditioning was mainly restricted to factories and a handful of public spaces. The initial invention is credited to Willis Carrier, an American engineer at a heating and ventilation company, who was tasked in 1902 with reducing humidity in a Brooklyn printing factory. Today we assume that the purpose of air conditioning is to reduce heat, but engineers at the time weren’t solely concerned with temperature. They wanted to create the most stable possible conditions for industrial production – and in a print factory, humidity curled sheets of paper and smudged ink.

Carrier realised that removing heat from the factory air would reduce humidity, and so he borrowed technology from the nascent refrigeration industry to create what was, and still is, essentially a jacked-up fridge. Then as now, air conditioning units work by breathing in warm air, passing it across a cold surface, and exhaling cool, dry air. The invention was an immediate success with industry – textile, ammunition, and pharmaceutical factories were among the first adopters – and then began to catch on elsewhere. The House of Representatives installed air conditioning in 1928, followed by the White House and the Senate in 1929. But during this period, most Americans encountered air conditioning only in places such as theatres or department stores, where it was seen as a delightful novelty.

It wasn’t until the late 1940s, when it began to enter people’s homes, that the air conditioner really conquered the US. Before then, according to the historian Gail Cooper, the industry had struggled to convince the public that air conditioning was a necessity, rather than a luxury. In her definitive account of the early days of the industry, Air-Conditioning America, Cooper notes that magazines described air conditioning as a flop with consumers. Fortune called it “a prime public disappointment of the 1930s”. By 1938 only one out of every 400 American homes had an air conditioner; today it is closer to nine out of 10.

What fuelled the rise of the air conditioning was not a sudden explosion in consumer demand, but the influence of the industries behind the great postwar housing boom. Between 1946 and 1965, 31m new homes were constructed in the US, and for the people building those houses, air conditioning was a godsend. Architects and construction companies no longer had to worry much about differences in climate – they could sell the same style of home just as easily in New Mexico as in Delaware. The prevailing mentality was that just about any problems caused by hot climates, cheap building materials, shoddy design or poor city planning could be overcome, as the American Institute of Architects wrote in 1973, “by the brute application of more air conditioning”. As Cooper writes, “Architects, builders and bankers accepted air conditioning first, and consumers were faced with a fait accompli that they merely had to ratify.”

Equally essential to the rise of the air conditioner were electric utilities – the companies that operate power plants and sell electricity to consumers. Electric utilities benefit from every new house hooked up to their grid, but throughout the early 20th century they were also looking for ways to get these new customers to use even more electricity in their homes. This process was known as “load building”, after the industry term (load) for the amount of electricity used at any one time. “The cost of electricity was low, which was fine by the utilities. They simply increased demand, and encouraged customers to use more electricity so they could keep expanding and building new power plants,” says Richard Hirsh, a historian of technology at Virginia Tech.

The utilities quickly recognised that air conditioning was a serious load builder. As early as 1935, Commonwealth Edison, the precursor to the modern Con Edison, noted in its end-of-year report that the power demand from air conditioners was growing at 50% a year, and “offered substantial potential for the future”. That same year, Electric Light & Power, an industry trade magazine, reported that utilities in big cities “are now pushing air conditioning. For their own good, all power companies should be very active in this field.”

By the 1950s, that future had arrived. Electric utilities ran print, radio and film adverts promoting air conditioning, as well as offering financing and discount rates to construction companies that installed it. In 1957, Commonwealth Edison reported that for the first time, peak electricity usage had occurred not in the winter, when households were turning up their heating, but during summer, when people were turning on their air-conditioning units. By 1970, 35% of American houses had air conditioning, more than 200 times the number just three decades earlier.

At the same time, air-conditioning-hungry commercial buildings were springing up across the US. The all-glass skyscraper, a building style that, because of its poor reflective properties and lack of ventilation, often requires more than half its electricity output be reserved for air conditioning, became an American mainstay. Between 1950 and 1970 the average electricity used per square foot in commercial buildings more than doubled. New York’s World Trade Center, completed in 1974, had what was then the world’s largest AC unit, with nine enormous engines and more than 270km of piping for cooling and heating. Commentators at the time noted that it used the same amount of electricity each day as the nearby city of Schenectady, population 80,000.

The air-conditioning industry, construction companies and electric utilities were all riding the great wave of postwar American capitalism. In their pursuit of profit, they ensured that the air conditioner became an essential element of American life. “Our children are raised in an air-conditioned culture,” an AC company executive told Time magazine in 1968. “You can’t really expect them to live in a home that isn’t air conditioned.” Over time, the public found they liked air conditioning, and its use continued to climb, reaching 87% of US households by 2009.

The postwar building spree was underpinned by the idea that all of these new buildings would consume incredible amounts of power, and that this would not present any serious problems in the future. In 1992, the journal Energy and Buildings published an article by the British conservative academic Gwyn Prins, arguing that the American addiction to air conditioning was a symbol of its profound decadence. Prins summarised America’s guiding credo as: “We shall be cool, our plates shall overflow and gas shall be $1 a gallon, Amen.”

During the time that air conditioning was reshaping America’s cities, it had little effect elsewhere. (With some exceptions – Japan, Australia and Singapore were early adopters.) Now, however, air conditioning is finally sweeping across the rest of the world. If the march of air conditioning across the US tracked its postwar building and consumption boom, its more recent expansion has followed the course of globalisation. As the rest of the world adopts more Americanised ways of building and living, air conditioning follows.

In the 1990s, many countries across Asia opened up to foreign investment and embarked on an unprecedented urban building spree. Over the past three decades, about 200 million people in India have moved to cities; in China, the number is more than 500 million. From New Delhi to Shanghai, heavily air-conditioned office buildings, hotels and malls began to spring up. These buildings were not only indistinguishable from those in New York or London, but were often constructed by the same builders and architects. “When you had this money coming in from the rest of the world for high-end buildings, it often came with an American or European designer or consultancy attached,” says Ashok Lall, an Indian architect who focuses on housing and low-energy design. “And so it comes as a package with AC. They thought that meant progress.”

As the rate and scale of building intensified, traditional architectural methods for mitigating hot temperatures were jettisoned. Leena Thomas, an Indian professor of architecture at the University of Technology in Sydney, told me that in Delhi in the early 1990s older forms of building design – which had dealt with heat through window screens, or facades and brise-soleils – were slowly displaced by American or European styles. “I would say that this international style has a lot to answer for,” she said. Just like the US in the 20th century, but on an even greater scale, homes and offices were increasingly being built in such a way that made air conditioning indispensable. “Developers were building without thinking,” says Rajan Rawal, a professor of architecture and city planning at Cept University in Ahmedabad. “The speed of construction that was required created pressure. So they simply built and relied on technology to fix it later.”

Lall says that even with affordable housing it is possible to reduce the need for air conditioning by designing carefully. “You balance the sizes of opening, the area of the wall, the thermal properties, and shading, the orientation,” he says. But he argues that, in general, developers are not interested. “Even little things like adequate shading and insulation in the rooftop are resisted. The builders don’t appear to see any value in this. They want 10- to 20-storey blocks close to one another. That’s just how business works now, that’s what the cities are forcing us to do. It’s all driven by speculation and land value.”

This reliance on air conditioning is a symptom of what the Chinese art critic Hou Hanru has called the epoch of post-planning. Today, planning as we traditionally think of it – centralised, methodical, preceding development – is vanishingly rare. Markets dictate and allocate development at incredible speed, and for the actual inhabitants, the conditions they require to live are sourced later, in a piecemeal fashion. “You see these immense towers go up, and they’re already locking the need for air conditioning into the building,” says Marlyne Sahakian, a sociologist who studies the use of air conditioning in the Philippines.

Over coffee recently in London, the influential Malaysian architect Ken Yeang lamented what he viewed as the loss of an entire generation of architects and builders to a dependency on fossil fuels to control the environment. “So much damage has been done by those buildings,” he says, “I have entirely lost hope in my generation; perhaps the next one can design a rescue mission.”

To its proponents, air conditioning is often presented as a simple choice that consumers make to improve their lives as they climb the economic ladder. “It’s no longer a luxury product but a necessity,” an executive at the Indian branch of the Japanese air-conditioner manufacturing giant Daikin told the Associated Press last year. “Everyone deserves AC.”

This refrain is as familiar in Rajasthan now as it was in the US 70 years ago. Once air conditioning is embedded in people’s lives, they tend to want to keep it. But that fact obscures the ways that consumers’ choices are shaped by forces beyond their control. In her 1967 book Vietnam, Mary McCarthy reflected on this subtle restriction of choice in American life. “In American hotel rooms,” she wrote, “you can decide whether or not to turn on the air conditioning (that is your business), but you cannot open the window.”

One step towards solving the problem presented by air conditioning – and one that doesn’t require a complete overhaul of the modern city – would be to build a better air conditioner. There is plenty of room for improvement. The invention of air conditioning predates both the first aeroplane and the first public radio broadcast, and the underlying technology has not changed much since 1902. “Everything is still based on the vapour compression cycle; same as a refrigerator. It’s effectively the same process as a century ago,” says Colin Goodwin, the technical director of the Building Services Research and Information Association. “What has happened is we’ve expanded the affordability of the air conditioner, but as far as efficiency, they’ve improved but they haven’t leaped.”

One scheme to encourage engineers to build a more efficient air conditioner was launched last year by the Rocky Mountain Institute (RMI), a US-based energy policy thinktank, and endorsed by the UN environment programme and government of India. They are offering $3m to the winner of the inaugural Global Cooling prize. The aim is to design an air conditioner that is five times more efficient than the current standard model, but which costs no more than twice as much money to produce. They have received more than a hundred entries, from lone inventors to prominent universities, and even research teams from multibillion-dollar appliance giants.

But, as with other technological responses to climate change, it is far from certain that the arrival of a more efficient air conditioner will significantly reduce global emissions. According to the RMI, in order to keep total global emissions from new air conditioners from rising, their prize-winning efficient air conditioner would need to go on sale no later than 2022, and capture 80% of the market by 2030. In other words, the new product would have to almost totally replace its rivals in less than a decade. Benjamin Sovacool, professor of energy policy at Sussex University and a lead author on the next Intergovernmental Panel on Climate Change (IPCC) report, describes this ambition as not impossible, but pretty unlikely.

“This idea of technology saving us is a narrative that we want to believe. Its simplicity is comforting,” he says. It has proven so comforting, in fact, that it is often discussed as if it is our first and best response to climate change – even as the timeframe for inventing and implementing such technologies becomes so narrow as to strain credulity.

New air-conditioner technology would be welcome, but it is perhaps “the fourth, or maybe fifth thing on the list we should do” to reduce the emissions from air conditioning, says Diana Ürge-Vorsatz, a professor of climate change and energy policy at Central European University, and a lead author on the forthcoming IPCC report. Among the higher priorities that she mentions are planting trees, retrofitting old buildings with proper ventilation, and no longer building “concrete and glass cages that can’t withstand a heatwave”. She adds: “All of these things would be cheaper too, in the long run.”

But while these things are technically cheaper, they require changes in behaviour and major policy shifts – and the open secret of the climate crisis is that nobody really knows how to make these kind of changes on the systematic, global scale that the severity of the crisis demands.

If we are not about to be rescued by technology, and worldwide policy changes look like a distant hope, there remains a very simple way of reducing the environmental damage done by air conditioning: use less of it. But, as the ecological economist and IPCC author Julia Steinberger has written, any serious proposals to change our lifestyles – cutting down on driving, flying or imported avocados – are considered “beyond the pale, heretic, almost insane”. This is especially true of air conditioning, where calls to use it less are frequently treated as suggestions that people should die in heatwaves, or evidence of a malicious desire to deny other people the same comforts that citizens in wealthy countries already enjoy.

This summer, the publication of a New York Times article asking “Do Americans need air conditioning?” touched off a thousand furious social media posts, uniting figures from the feminist writer and critic Roxane Gay (“You wouldn’t last a summer week in Florida without it. Get a grip”) to the conservative professor and pundit Tom Nichols (“Air conditioning is why we left the caves … You will get my AC from me when you pry it from my frozen, frosty hands”).

Despite this backlash, there is a reasonable case to be made that we are over-reliant on air conditioning and could cut back. The supposedly ideal indoor temperature has long been determined by air-conditioning engineers, using criteria that suggest pretty much all humans want the same temperature range at all times. The underlying idea is that comfort is objective, and that a building in Jakarta should be the same temperature as one in Boston. In practice, says Leena Thomas, this means that the temperature in most air-conditioned buildings is usually “low-20s plus/minus one”.

But not everyone has accepted the notion that there is such as thing as the objectively “right” temperature. Studies have suggested that men have different ideal temperatures from women. In offices around the world, “Men toil in their dream temperatures, while women are left to shiver,” argued a 2015 article in the Telegraph, one of many suggesting that the scientific research had simply confirmed something millions of women already knew.

Researchers have also shown that people who live in hotter areas, even for a very short time, are comfortable at higher indoor temperatures. They contend that, whether it is a state of mind or a biological adjustment, human comfort is adaptive, not objective. This is something that seems obvious to many people who live with these temperatures. At a recent conference on air conditioning that I attended in London, an Indian delegate chided the crowd: “If I can work and function at 30C, you could too – believe you me.”

Adding to the weight of evidence against the idea of the “ideal” temperature, Frederick Rohles, a psychologist and member of the American Society of Heating, Refrigerating and Air-Conditioning Engineers, has conducted studies showing that subjects who were shown a false thermometer displaying a high temperature felt warm, even if the room was cool. “These are the sorts of things that drive my engineering colleagues crazy,” he wrote in 2007. “Comfort is a state of mind!”

Ashok Lall points out that once people are open to the idea that the temperature in a building can change, you can build houses that use air conditioning as a last resort, not a first step. “But there is no broad culture or regulation underpinning this,” he says. At the moment, it is the deterministic camp that has control of the levers of power – and their view continues to be reflected in building codes and standards around the world.

How, then, can we get ourselves out of the air-conditioning trap? On the continuum of habits and technologies that we need to reduce or abandon if we are to avoid the worst effects of the climate crisis, the air conditioner probably falls somewhere in the middle: harder to reduce than our habit of eating meat five times a week; easier than eliminating the fossil-fuel automobile.

According to Nick Mabey, a former senior civil servant who runs the UK-based climate politics consultancy E3G, air conditioning has – like many consumer products that are deeply embedded in society and, in aggregate, drive global warming – escaped the notice of most governments. There is little precedent for top-down regulation. “There is no department that handles this, there’s no guy you can just go talk to who controls air conditioning,” he says.

The key, Mabey says, is to find the places it can be controlled, and begin the push there. He is supporting a UN programme that aims to improve the efficiency – and thus reduce the emissions – of all air conditioners sold worldwide. It falls under the unglamorous label of consumer standards. Currently, the average air conditioner on the market is about half as efficient as the best available unit. Closing that gap even a little bit would take a big chunk out of future emissions.

At the local level, some progress is being made. The New York City council recently passed far-reaching legislation requiring all large buildings in the city to reduce their overall emissions by 40% by 2030, with a goal of 80% by 2050, backed with hefty fines for offenders. Costa Constantinides, the city council member spearheading the legislation, says it is “the largest carbon-emissions reduction ever mandated by any city, anywhere”. The Los Angeles mayor’s office is working on similar plans, to make all buildings net-zero carbon by 2050.

Other cities are taking even more direct action. In the mid-1980s, Geneva, which has a warmer climate than much of the US, the local government banned the installation of air conditioning except by special permission. This approach is relatively common across Switzerland and, as a result, air conditioning accounts for less than 2% of all electricity used. The Swiss don’t appear to miss air conditioning too much – its absence is rarely discussed, and they have largely learned to do without.

In countries where air conditioning is still relatively new, an immense opportunity exists to find alternatives before it becomes a way of life. The aim, in the words of Thomas, should be to avoid “the worst of the west”. Recently, the Indian government adopted recommendations by Thomas, Rawal and others into its countrywide national residential building code (“an immensely powerful document” says Rawal). It allows higher indoor temperatures based on Indian field studies – Indian levels of comfort – and notes the “growing prevalence” of buildings that use air conditioning as a technology of last resort.

Cutting down on air conditioning doesn’t mean leaving modernity behind, but it does require facing up to some of its consequences. “It’s not a matter of going back to the past. But before, people knew how to work with the climate,” says Ken Yeang. “Air conditioning became a way to control it, and it was no longer a concern. No one saw the consequences. People see them now.”

• This article was amended on 29 August 2019. The photo of Willis Carrier is from the New York World’s Fair in 1939, not the St Louis World’s Fair in 1904 as stated in an agency-provided caption in an earlier version.

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