Most people dread going outside in the sweltering summer heat, but for Jiang Mingying, taking refuge in an air-conditioned home is not an option. Jiang lives in a 450 sq ft walk-up apartment with eight others in Sham Shui Po, one of Hong Kong’s most densely populated and poorest districts. Hot summer nights could be bigger killers than daytime scorchers, Hong Kong researchers say She spends most of her nights cooped up in her 40 sq ft cubicle which is boarded up with wooden partitions. There are no windows and it is just enough to fit a bed, a refrigerator, an electric fan and a small table. “You can’t breathe here. During the summer I’m outside in the park or in McDonald’s at least five or six days a week. It’s much cooler,” Jiang said, fanning herself with a leaflet. “It’s worst at nights with the bed bugs. Sometimes it feels like a prison. If I was a man, I’d sleep outside all day and night,” she said. Jiang is just one of some 200,000 people living in 88,000 subdivided flats who had to endure poorly ventilated, cramped spaces when temperatures soared to 34 degrees last month. A recent survey conducted by the Society for Community Organisation found that the temperatures inside the packed homes of 29 families averaged 34 degrees Celsius – one to four degrees higher than outdoors. In a changing climate, Hong Kong must prepare itself for much worse than a heat wave The highest was 37 degrees inside a rooftop shack in Sham Shui Po, the district where Jiang lives. Jiang said she had to call an ambulance last year after suffering an asthma attack. “If the ambulance came two minutes later I wouldn’t have made it. The only reason I’m sick is because I’ve been living here in conditions like this,” she said. “I could die in my sleep at night [from the heat] and no one would even know,” she said. Hong Kong is on track to experience possibly one of the hottest years on record, with the number of “very hot weather” warnings issued last year at an all-time high since records began in 1884. Hong Kong clocked up 38 very hot days and 36 hot nights last year, when temperatures went past 33 and 28 degrees respectively, according to the Observatory. Despite the scorching summer temperatures, using an air conditioner isn’t the best way to cool off, according to the Observatory’s former director and environmentalist Lam Chiu-ying. “We haven’t turned on the air conditioner in our home for eight years. We got by just using electric fans,” Lam said. Can you handle the heat? Hong Kong Observatory director forecasts more extreme weather after record-breaking years Lam’s electricity bill adds up to HK$100 a month in the summer – 10 times less than what he would be paying if he had turned on an air conditioner. “A lot of people underestimate how effective an electric fan is. Actually studies show that as long as you have a light, constant breeze directed at your head and upper body, you don’t feel so hot any more,” he said. According to Lam’s calculations, using a USB electric fan can be an affordable solution even for subdivided flat residents with poor ventilation. “Even if you keep a USB electric fan on for 24 hours, 365 days a year, you are only generating 22 kWh of electricity. That means you only have to pay HK$26 a year for electricity if you’re living in Kowloon,” Lam said. Lam explained that those living in cramped quarters could use a small fan used to cool gaming computers to increase ventilation by attaching it to their window. “If one thing needs to be changed, it’s the mentality that sweating in summer is dirty or not hygenic. You should be sweating, that means your body is working,” he said.