Hong Kong average temperature

It was just one night but it seems most people in Hong Kong could not go without air conditioning. Last Wednesday, 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.