Debate: Heating system
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Does South China need a central heating system? "No", says one expert, because it would be an unnecessary drain on precious energy, while another says it is important to restructure the entire system to save energy.
Jiang Yi: South too warm for central heating
As winters get colder, more people are urging the government to build a central heating system in South China too. But few among these people have thought about factors such as efficiency and differences in climate in northern and southern China.
Since ancient times, Chinese people have recognized the Qinling Mountain Range and the Huaihe River as the geographical line dividing northern and southern China. North China needs a central heating system because its weather is much colder than that of South China. Winter in northern China is much colder and longer than in the southern parts. Winter lasts up to six months in Northeast China, where temperatures can drop to minus 40 C. Compared to the northern parts, winter in South China is warmer and shorter. Temperatures in South China are usually above freezing point in winter. In fact, in some places winter lasts little more than a month.
In other words, central heating is a necessity for people in North China, whereas it is needed in the southern parts to make people more comfortable.
True, people living just south of the geographical dividing line feel the harshness of winter as much as their northern neighbors. But then there has to be some point of reference for the geographical division, or else the boundary will keep shifting southward until it reaches the South China Sea.
In South China, the difference between indoor and outdoor temperatures in winter is less than 10 C. Indoor temperatures usually are around 14 C to 16 C, while outdoor temperatures vary between 6 C and 10 C. But in North China, the difference is far greater, often more than 20 degrees. Without proper heating, the cold in such places will take a toll even on people who stay indoors, reducing their efficiency and causing illness and fatalities.
Installing a centralized heating system in areas where indoor and outdoor temperatures don't vary much makes little sense. Instead, local heating with intermittent supplies should be enough to make winters relatively warmer indoors in such areas.
Take major cities like Nanjing and Shanghai in South China as examples. If people there use their air conditioners to keep their houses warm in winter, they would be using 6 to 8 kilowatts of electricity per square meter per month, which is equivalent to burning about 3 kg of coal. But 20 kg of coal would be required to keep one square meter of indoor space warm for a month through a central heating system.
This should give people an idea of how heavy the energy burden would be if central heating is introduced in the southern part of China.
Another factor worth mentioning is the change that central heating brings about in people's habits. Before central heating was introduced in the 1950s, people in North China used traditional means such as stoves or charcoal to keep their houses warm in winter and wore more clothes indoors than they today.
But the central heating system has made winter so warm indoors that people wear fewer clothes at home. Some houses are so warm that a person feels comfortable even in a T-shirt. Temperatures in some offices are as high as 30 C, and many department stores, malls and supermarkets often maintain temperatures above 20 C, when 18 C is enough to keep indoors warm in winter. This is unnecessary waste of energy.
If central heating system is introduced in South China, the same story would be repeated there, and it would be repeated for a something that is not necessary. This is against the energy conservation policy of the government.
Lessons can be learned from countries such as Japan, too, which don't have a central heating system even though the difference between outdoor and indoor temperatures vary little in that country's northern and southern parts.
A central heating system is not the required in China's southern areas because the weather there is much warmer that North China and to prevent unnecessary waste of energy. Besides, it will cost astronomical amounts to build, run and maintain a central heating system in South China. That would be unnecessary expenditure because, unlike the northern parts, the central heating system in South China would be operational for only two months.
Hence, a better and more environmentally friendly way of keeping houses, offices and factories warm in winter in South China would be to use local heating systems like fireplaces, air conditioners and stoves.
The author is a professor at the School of Architecture, Tsinghua University.
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