Southern cities strive to address indoor heating concerns as temperatures fall

"The temperature is around 25 C when the heating is on, and we just wear thin clothes indoors," he said. "Sometimes we have to open windows to let cold air lower the room temperature."

Financial pressures and environmental concerns have limited the development of unified heating in Wuhan, according to the energy department of the city's development and reform commission, but it said it is making plans to construct two more large-scale energy stations to provide heating to four of its districts.

Zhang, from Southeast University, suggested that instead of simply adopting North China's unified heating, cities in the delta should use new heating techniques that not only meet people's demands but also save energy.

He and his team are researching high efficiency heat pump technology, which can transfer heat from low temperature sources to high temperature sources. It has been used in some programs in Yangzhou and Changzhou of Jiangsu province.

Ma Lin, deputy manager of Jiangbei New Energy Development and Management Company in Nanjing, said Nanjing's Jiangbei New Area will use the heat pump technology to provide heat to some public buildings this winter.

"The water of the Yangtze River is colder than the buildings onshore in summer and warmer in winter," he said. "The technology can transfer the heat from the buildings to the river in summer, and transfer the heat from the river to the buildings by using heat pumps in winter."

According to Ma, construction of the two energy stations will be completed in February and provide heat to buildings covering 3 million sq m. Upon completion of seven energy stations, people will enjoy heat in buildings covering 16 million sq m in downtown Jiangbei New Area.

Zhou Lihua in Wuhan and Feng Zhiwei in Changsha contributed to this story.