It was just one night, but it seems most people in Hong Kong could not go without air conditioning. On September 29, about 50,000 households switched off their air-con units for Hong Kong’s first No Air Con Night, an event organized by the eco-group Green Sense to raise awareness of the environmental impact of air conditioning.
But for the remaining 2,285,000 homes in the city, it was business as usual.
“I tried to sleep without the A/C on, but it was too noisy to keep the windows open and the room heated up so fast,” one Mongkok resident said.
In just a few decades, Hong Kong has evolved into an air-con dependent city, with most people spending their days in housing estates, shopping malls and office towers that become furnaces without the cooling systems. The dependence continues at night as temperatures soar in our high-rise, heat island homes. So much so that air con accounts for 60 per cent of the city’s power consumption in summer.
When it comes to air conditioning, we seem to have built ourselves into a corner. Now, some are looking for a way out.
“Even in the 1990s, schools were not air conditioned, many buses had no air con and there were not as many shopping malls,” said Gabrielle Ho, the project manager of Green Sense. “Now the first thing people do when they get home is switch on the air con. Everywhere is so air-conditioned, people have gotten used to it.”
Given that Hong Kong’s average temperature is rising by as much as 0.6 degrees Celsius per decade -– more than three times faster than the world average –- it’s not hard to see why air conditioning has become ubiquitous.
One of the most noticeable effects of the rise in temperatures is the higher frequency of hot nights, when the mercury does not dip below 28 degrees. In the early 1950s, there were no such nights, according to the Hong Kong Observatory. Now there are more than 20 per year.
Much of this is due to the urban heat island effect, when materials like concrete and asphalt absorb heat during the day and release it at night. Hong Kong’s densely-packed high-rises only aggravate the problem, creating a “wall effect” that reduces air circulation in many neighbourhoods. But excessive air conditioning is also a big reason for the climbing temperatures.
Hong Kong’s densely-packed high-rises only aggravate the problem. The so-called wall effect reduces the air circulation in many neighbourhoods. Even worse, many Hong Kong apartment buildings are designed in such a way that air conditioning units are just 10 to 30 centimetres away from the living rooms of adjacent flats. A study released by Green Sense earlier this week revealed that 53 percent of Hong Kong’s residents switch on their air conditioners because their neighbours’ air conditioners blew hot air directly into their flats.
“It’s a vicious cycle, because the more we use air conditioning, the hotter it gets, and the more we need to use it,” said Angela Tam, the author of Sustainable Building in Hong Kong, which outlines how Hong Kong can be developed in a more environmentally-friendly way. “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.”
That wasn’t always the case.
“If you look at colonial Hong Kong, there were all sorts of things that were intended to cool the city,” said Jonathan Solomon, an assistant professor of architecture at the University of Hong Kong. Streets were often lined by large trees, sidewalks were covered by arcades, apartments had high ceilings, large windows and deep verandahs that could be shaded by bamboo screens. The barriers between interior and exterior space were fluid.
“Now it’s hotter outside and colder inside than it ever was before,” said Solomon. His latest research project looks at the interconnected interior spaces that have been built throughout the city. In theory, it is possible to travel from a Central office to a home in Tseung Kwan O, by way of MTR, without ever setting foot outdoors. “It’s a new form of urban fabric that has arisen because of the ubiquity of air conditioning,” he said.
That isn’t the case in other cities. Solomon recently spent a week in Singapore, where he noticed that people adapted more readily to the hot weather than in Hong Kong. More people dressed in short sleeves and sandals and there was more emphasis on outdoor spaces like hawker centres, he said. “There’s a lot more cultural adaptation. In Hong Kong, it’s so violently air conditioned I have to keep a sweater around all summer long.”
In the 1969 book Architecture of the Well-Tempered Environment, the historian Reyner Banham argued for an approach to architecture that considered the relationship between technology, human needs and the environment. Until recently, though, Hong Kong developers and architects have paid little heed to that advice. “You end up having the barnacles of air conditioning units all over the place,” said David Erdman, an architect based in Wan Chai. “Having them all over the exterior is a clear sign that you don’t see air conditioning as part of the building. You’re rejecting it.”
In their residential projects in Hong Kong, Erdman and his partner, Clover Lee, try to reduce the impact of air conditioning by integrating it into their designs and using materials that keep homes cool in hot weather. “It’s one of the first things we think about,” he said. “Sustainability at this point is a fact, like structural engineering,” he said. “It has to happen.”
Other architects, like Eric Schuldenfrei and Marisa Yiu, who run the research-based design firm eskyiu, have also considered ways to reduce Hong Kong’s dependence on air conditioning. “It’s crazy these days because architects no longer learn how to design a building that ventilates naturally,” said Schuldenfrei. The pair is working on a concept for an Aberdeen tower that would use greenery and seawater to cool itself.
But old habits are hard to break. “Everyone wants a comfortable environment — that’s the first thing on their minds,” said Erdman. And for now, air conditioning remains the preferred way for people in Hong Kong to stay cool.
No government officials participated in No Air Con Night, aside from Environment Secretary Edward Yau Tang-wah and Hong Kong Observatory director Lee Boon-yin. The government has long promoted the use of energy-efficient and water-based air conditioning systems. It also maintains a temperature of no less than 25.5 degrees in its offices and encourages – but does not require – others to do the same.
Other governments around Asia, which is the world’s fastest-growing market for air conditioning, have taken a more aggressive stance against excessive air con use. In June, Taipei’s municipal government passed a law prohibiting businesses from setting their air conditioners to less than 26 degrees; those who do not comply risk being fined up to HK$12,400.
“What we really need to talk about is changing our lifestyles,” said Lee. “I always encourage people to use electric fans but some don’t even own them anymore.” Even more energy-efficient air conditioning units would reduce electricity consumption by less than 30 percent, he said, so the only way to make things better is to use less air conditioning, wear appropriate summer clothing and spend more time outdoors.
Even then, things are going to get worse before they get better: the Observatory predicts that the annual number of hot nights will increase from 20 today to more than 55 by 2029.
“If that’s the case, our use of air conditioning will only increase,” said Lee. “We don’t see any signs of improvement.”
A version of this story was published in the October 3, 2010 edition of the South China Morning Post.
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