Get us in your inbox


Hong Kong's air con abuse: Is it time to turn it down?

Written by
Anna Cummins

Despite the recent cold snap, air conditioning across the city has been pumping resolutely on. Anna Cummins and Jocelyn Wong wrap up and head out to explore why we just can’t switch it off. Photography by Calvin Sit

With the mercury dropping to an unusually frigid seven degrees Celsius during mid-February, Hongkongers have, sensibly, been wrapping up extra-warm. Yet, while being cold outside is unavoidable, we’ve also been staying wrapped up inside – for the air conditioning has been blasting merrily away in our city’s shopping centres, cinemas, offices and restaurants, in spite of the cold snap. This incongruous situation begs the question: is Hong Kong abusing its air con? One thing’s for sure. For this debate, the (woollen) gloves are staying firmly on.

‘Cold air machines’ (as they’re known in Cantonese) are a way of life in our city, no matter the time of year. Many people would confess to owning an ‘indoor’ jacket – and some tourist guide publications warn prospective travellers about ‘transport and buildings that blast out cold air’. Air conditioning chugs about 30 percent of all electricity used in the city annually. It’s closer to 60 percent in the summer. This is, of course, far from eco-friendly. It takes a mature tree three months to absorb the carbon emissions created by just one regular air con unit in eight hours.

We brave the chill and set out to quiz people on the matter. In a Taste supermarket inside Festival Walk in Kowloon Tong, we record temperatures of a staggering 12 degrees Celsius in the aisles – on a day when it’s 17 degrees outside. A representative of the management team at the store simply tells us ‘this is an order [from higher management]… I have no input whatsoever,’ before adding ‘it’s not that cold [in here]’.

These opinions are echoed in IFC mall –  temperatures outside are 18 degrees, but we find temperatures as low as 15 degrees inside. A representative of the mall’s management office tells us the indoor temperature ‘is not my jurisdiction’ and that ‘it isn’t that cold anyway’.

Feel the drop: Indoor temperatures can be uncomfortably low

Passengers on a 101 bus heading towards Kennedy Town during rush-hour also seem unconcerned about the cold air pumping through the vehicle. “Without [air con], it would get too stuffy,” a young man named Siu Fai tells us. “It’s necessary to create a people-friendly environment.” Fellow passenger Sarah Tang says: “People need air conditioning in densely populated areas. It provides circulation – otherwise it could create a place for infection or asthma.”

So we contact bus operator KMB to ask about its policy. While environmental guidelines suggest keeping temperatures at 24 to 26 degrees, the firm tells us that the thermostat in its fleet is set at 23 degrees. The air con on the company’s buses is constantly switched on – and the driver cannot adjust the system. “The A/C is not only concerned with the temperature,” says a KMB spokeswoman. “It is concerned with the humidity, air flow and reduction in dust. If you turn off the A/C there is no fresh air in the bus, as the windows cannot open.”

Lars Kirchhoff, operations director of local air quality solutions company Clairzone, disputes the widely held opinion that air conditioning increases circulation of ‘fresh’ air, pointing out that the outdoor air in the city is far from ‘fresh’ anyway. “There are a lot of misconceptions about air conditioning in Hong Kong and the rest of the world,” he says. “People often mistake air con for supplying fresh air to an indoor space, but in reality, it’s just recycling the same air over and over again over a pair of cooling coils. There’s no outdoor or ‘fresh’ air involved. And there’s technically very little air cleaning involved too.” 

Kirchhoff tells us that air conditioners only catch large particles. Bacteria, viruses and the numerous pollutants from our outside air are not caught by the mesh filters in the machines. These filters, if not maintained and cleaned, can become a breeding ground for bacteria. “As a matter of fact, air con frequently aggravates the indoor air pollution, rather than making it better,” he says. The World Health Organisation has long acknowledged that inadequate ventilation is an important contributor to ‘Sick Building Syndrome’ – when exposure to poor air leaves occupants of a building feeling unwell. 

It’s fairly shocking then that, especially during winter, the air con is being blasted simply to maintain ‘circulation’, rather than out of a need to lower temperatures. Worse still, our city’s indoor air quality is pretty poor, according to Clairzone’s service director and local air quality expert, KC Barton Wong, who says that many large commercial buildings also turn off their ‘fresh air handling units’ in favour of recirculating the already-chilled air through the system. “This can save a couple of million dollars every year,” he points out. Wong confirms that he has recorded CO2 levels of 3,000ppm (parts per million – a unit of measurement for carbon dioxide) inside local shopping centres. This is three times higher than the generally accepted level, potentially triggering tiredness, headaches and dizziness.

Colder and colder: These small white boxes are a familiar fixture

Of course, Hong Kong has a short winter and it’s necessary to lower temperatures indoors somewhat during the long, hot summer. But is it essential to induce such deeply low temperatures that jackets are required year-round? Many seem to think so. “Hong Kong people are used to more moderate temperatures,” says Tommy Chan, who we speak to while he’s shopping at iSquare mall. “Intense heat would discourage people to go into malls, thinking they are more primitive.” Fellow shopper Fiona Li agrees. “Low indoor temperatures are not very environmentally friendly – but it is a good escape for people who are hot on the street.” 

Local eco group Green Sense organises an annual ‘no air con night’ to highlight the environmental impact of using all this electricity. Project manager Gabrielle Ho worries that prevailing attitudes are hard to change. “People think that if you’re too cold, you can bring a jacket or scarf, but if you’re too hot, you can do nothing – it’s usual that companies will turn the air con lower to provide comfort to more people.” Ho points out that the heat pumped into the street by air conditioning units contributes heavily towards the ‘urban heat island’ effect, which conversely means people feel hotter and need to be cooled down more. 

There is some glimmer of hope for a change in attitude – a record 75,000 households took part in ‘no air con night’ in September last year, and 120 malls, 550 shops and 170 office buildings are now signed up to the government’s ‘energy saving charter’, promising to maintain indoor temperatures of 24 to 26 degrees during summer. “That’s a very good start,” says Ho. “If more and more companies work on this issue, more people will be aware of the problem: that we are abusing the air conditioning in Hong Kong.”

Attitudes may be changing slowly, but we’re pretty sure it’s going to take a long time to wean our city off its cold air addiction. Don’t throw away that indoor jacket just yet…

For more information on the energy saving charter, see

Latest news