There are maps that help you find your way around, and there are maps that reveal the underlying truth about a place. In Cities Without Ground, a 2012 book by architects Clara Wong, Adam Frampton and Jonathan Solomon, contains many of the latter. One of them is a map that records the temperature in the complex web of indoor and outdoor settings that make up public space in Central. And the truth it reveals is just how extreme Hong Kong’s air conditioning habit has become.
Under the baking sun of a summer afternoon, the concrete driveway of the British consulate was an unforgiving 33.6 degrees Celsius. Just a few steps away, amidst the climate-controlled shops of Pacific Place, the temperature was 23.1 degrees. And in the MTR trains that run beneath it all? A chilly 20.5.
“It’s hotter outside and colder inside than it ever was before,” said Solomon when he was conducting the research. The weather records bear him out. Between 1991 and 2020, Hong Kong’s average temperature rose by 0.24 degrees per decade – twice the rate of increase as in the previous hundred years. The number of hot nights, when the temperature at the Hong Kong Observatory does not dip below 28 degrees, is growing exponentially, with 50 recorded last year, compared to 24 a decade earlier and just one or two in the years before 1980. Climate change means the world is growing hotter, and Hong Kong is heating up at an even faster rate than most other places.
The response has been to crank up the air conditioning, which accounts for a whopping 60 percent of Hong Kong’s energy use during the summer months. But even winter offers little respite. In February 2016, journalists Anna Cummins and Jocelyn Wong discovered that, with air con blasting even during cold snaps, indoor spaces are often colder than the outdoors. Parts of IFC Mall were 15 degrees when it was 18 degrees outside – and a supermarket in Kowloon Tong was a positively frigid 12 degrees. “Without [air con], it would get too stuffy,” a young man riding a chilly bus told the reporters. “It’s necessary to create a people-friendly environment.”
But that isn’t the case in many other cities with hot climates. In Taipei, businesses risk large fines if they set their air conditioners to less than 26 degrees. Singapore’s government has long encouraged naturally ventilated spaces and climate-appropriate attire. When you cross the border from Hong Kong to Shenzhen, the ambient indoor temperature is notably warmer. So how did Hong Kong become so addicted to air conditioning?
For thousands of years, people have been cooling their indoor environments through passive techniques like shaded verandahs and building designs that amplify natural air flow. In the 19th century, scientists began experimenting with compression technology that used compressed and liquefied ammonia to artificially cool air. At first, this approach was used primarily to manufacture ice, but when electricity became more widespread, an American inventor named Willis Carrier took advantage of it to create the world’s first electrical air conditioning unit. He unveiled his creation in 1901 and installed the first air conditioning system the following year.
At first, air conditioning was used mainly by industry to benefit manufacturing processes that were sensitive to temperature and humidity, like printing presses. But the first residential air conditioning system was installed in 1914, in Minneapolis, and window-box air conditioners were invented in 1931, making it possible for anyone to cool their home. That is, if they could afford it – those early units cost around US$120,000 in today’s money.
The high cost of early air conditioning meant it was limited to businesses that could use it to their advantage. In Hong Kong, the very first air-conditioned space was the King’s Theatre on Des Voeux Road Central, which unveiled its newly refrigerated auditorium in 1931. By today’s standards, the cooling effect was modest. “The scale on which the King’s plant works is to maintain the humidity inside the theatre at 60 percent, and to regulate the temperature inside on a scale a few degrees below that of the outside air,” reported The Hong Kong Telegraph. If the temperature outside was 32 degrees, the air conditioning was set to 25 – warmer than a typical cinema today, but no doubt a huge relief for moviegoers looking to escape a muggy Hong Kong summer.
The first fully air-conditioned building in Hong Kong was the third-generation HSBC headquarters, which opened on Statue Square in 1935. It instantly became the most coveted property in Hong Kong, with establishments like the American Club ditching their old premises in favour of air-conditioned digs in the new building. A few years later, the Telegraph ran a story, “How Air Conditioning Can Come to the Relief of Mankind,” that examined how climate control might change Hong Kong. “Local architects estimate that, per square foot of floor area, occupants of offices will pay as much as 50 percent more for premises air-conditioned,” the paper noted. The physical shape of buildings would change, too: whereas a standard Hong Kong office at the time had 18 foot ceilings, those could be lowered to 13 in new air-conditioned buildings.
Even as air conditioning became popular in offices, cinemas and hotels, however, it was a rare luxury in Hong Kong homes. In most cases, they were simply too expensive and too cumbersome. Although one local factory did produce air conditioners licensed under the American brand Westinghouse, they were mostly intended for export. And they were bulky. “The early ones were huge, three feet by four feet and three feet tall – sounds like a locomotive,” recalls Sam Lok, whose family bought a unit in 1954.
Lok is a member of Hong Kong in the 1960s, a popular Facebook group. When we asked other members about their experience with air conditioning, it triggered a lively response. Many remember that, even if they had air con, its use was limited. “[We] only had air conditioning in my parents’ bedroom in the late 60s – children didn’t need it!” recalls Alison Croucher. “However, if my parents went out for the evening, we would drag our mattresses into their bedroom. On their return it was quite a surprise for them.”
Samantha Sawyer spent two years in Hong Kong with her family, who had no air conditioning. “I remember as a child the sleepless nights staring at the ceiling fan rotating,” she says. Caroline Spencer lived with her family on the Stonecutters Island naval base in the early 1960s. “We had a dehumidifying room where our books and clothes were kept,” she recalls. “We slept on rattan mats under mosquito nets with all the windows wide open. Not at all comfortable in the summer.”
Things began to change in the 1980s when air conditioners became more affordable – and Hong Kong became more prosperous. “We never had air conditioning in the 60s,” says Hong Kong in the 60s member Christine Mark. “When we returned in the 80s, we were amazed by the proliferation of air conditioners.” New buildings built after the 1980s usually included a hole in the walls of each room where residents could slot in an air conditioner. Not coincidentally, the 1980s marked the time when Hong Kong’s climate began warming significantly. The city’s average temperature climbed half a degree, from 23 to 23.5, over the course of that decade.
But air conditioning still wasn’t as ubiquitous as it is today. KMB introduced its first air-conditioned bus in 1985, and it was such a novelty, it had a distinct livery: white and red, as opposed to the cream and red colour scheme used by the famous “hot dog buses” that had no climate control. (It’s not entirely clear why “hot dog,” or jit6 gau2 (熱狗), was used to describe these buses, but on a sticky summer night when one sat on the upper deck, it certainly felt appropriate.) Most schools lacked air conditioning well into the 1990s.
Now it’s virtually impossible to escape it. Over the course of the 1990s, Hong Kong seems to have reached a tipping point in which air conditioning became utterly ubiquitous. According to government data, more than 99 percent of Hong Kong homes are air-conditioned. People spend their leisure time in perpetually climate-controlled malls. The last hot dog bus was retired in 2012. (If you want to get around town without feeling like you’re in a refrigerator, your only real choices are to walk or take the tram.) Most people carry a sweater or jacket around in the summer to wear when they are indoors; in one survey conducted by environmental group Green Sense, 50 percent of respondents said they consider their office air conditioning to be “cold” or “very cold.” Unlike Singapore, where light summer clothing has become acceptable in the office, it’s not uncommon for people in Hong Kong to wear full suits even when the outdoor temperature soars into the mid-30s.
The consequences can be dire. Most of Hong Kong’s electricity comes from dirty sources like coal, so the more air conditioning is used, the more carbon is pumped into the atmosphere, worsening the climate crisis. And yet the hotter Hong Kong gets, the more air conditioning becomes essential. “It’s a vicious cycle,” says Angela Tam, author of Sustainable Building in Hong Kong. “You can’t just talk about air conditioning, you have to talk about the whole urban form. Given the way Hong Kong is built, there’s no way for heat to disperse.”
The city’s density and lack of urban greenery means the urban areas do not cool off at night, making them dangerously hot. And many buildings are designed in such a way that air conditioning units blow their exhaust directly into adjacent windows. One Green Sense survey found that 53 percent of respondents switch on their air conditioning because their neighbours’ units make it too noisy, hot and unpleasant to keep the windows open.
It’s a complicated situation. When summers are becoming longer, hotter and more intense, it’s only natural to seek out air-conditioned spaces. But Hong Kong has probably crossed the line into excess. Do MTR trains really need to be a full 10 or even 15 degrees colder than the weather outside? Is it really appropriate to wear a suit and jacket in the middle of July? And there’s another, bigger question to be asked, too. If Hong Kong doesn’t cut back on its air con habit, what happens next?