The apartments in HK do not shield against the elements. It is hot in the summer and cold in the winter, if there is one, as soon as one turns off the A/C / heater. Although the rate may be different, same utility bill amount for a 400 square feet apartment in HK as a 2500 square feet house in US.I love it when my friends in North America feel so proud about how they recycle eveything, and then jump into their gas guzzler SUVs and blast the heat in their gigantic 5 to 7 room houses all winter long. It's feelgood environmentalism without actually taking a hard think about changing lifestyle habits which could make a real difference.
Per capita emissions in HK are low because such a good chunk of the 7m people here are poor by most standards with no hopes of car ownership or not living in a shoebox with 2-5 other people. Due to poverty the per capital emssions are low, not due to choice so I would not give HK people too much credit.