When Jack Frost comes knocking at your window, a rumble of griping will be heard from southern China, calling for central heating.

Here in Beijing, every household is heated from mid-November through mid-March of the following year, shielding residents from the bitter cold. But in Zhejiang province, where I grew up, winter is an ordeal. In the daytime, we'd rather stay outdoors for some sunlight. When night falls, it is just as freezing inside the home as outside.

The most excruciating moments were getting into bed and getting out of it. It was like taking a dip in freezing weather. We would put under the blanket glass bottles filled with hot water or even bronze containers with charcoal, but none were ideal. The bottle would cool down in minutes and the bronze container was a fire hazard. In the morning you would not want to get up because the bed was sufficiently warmed up from your body heat but the room was still chilly.