The cold front that has swept across much of the country is creating hot opportunities.

But in a surprising twist, stores selling electric heaters have been cold-shouldered.

Old-fashioned bed warmers, bronze pots that can be filled with hot water and then sealed, are doing a roaring trade, as are hot springs.

Resorts in the Yangtze River Delta, where there is no citywide heating system as there is in northern cities like Beijing, have been inundated with bookings and queries.

"We are very busy," said Pan Kang, sales manager of a hot spring in Nanjing.

The phone has been ringing constantly with potential customers inquiring about the resort's 198-yuan-a-day ($31) package.

At the weekend, the resort received about 4,000 people a day, mostly group visitors from neighboring cities such as Shanghai, Suzhou and Wuxi.

He is confident that bookings will continue to rise.

Another hot spring in Nanjing refused to talk to China Daily on the phone because it was "afraid that media exposure will bring more customers to our already crowded pools".

Over the weekend, East China experienced its lowest temperature this winter, with mercury dipping to as low as -6 C.

Long lines formed outside the Zhang Xiaoquan store on Shanghai's bustling East Nanjing Road to snap up traditional bronze bed warmers for 300 yuan.

"I have been selling them for decades, but I have never seen demand like this before," said Wang Zheng, a shop assistant at the store.

Bed warmers have been flying off the shelves at a rate of about 300 a day and suppliers are having difficulty meeting demand.

More than 17,000 have been sold so far this winter, almost double normal sales for the whole season.

They are cheaper to use in the long run than electric heaters and evoke a sense of nostalgia for the "good old days", Wang said.

Stores selling herbal paste and traditional Chinese medicine have also seen brisk business.

The paste, meant to be good for digestion and said to give a warm feeling inside, costs 3,000 yuan, almost three times the price of five years ago.

Doctors have also been unusually busy with patient numbers tripling.

"I often see up to 40 patients in one day," said Qu Lifang, a doctor in Shanghai who specializes in traditional Chinese medicine.

Warm clothing is also a hot item. Taobao.com, China's largest online marketplace, said that there has been a 200 percent rise in the sales of down jackets on the site.

There are more orders for the coats from Jiangsu and Zhejiang provinces than anywhere else.

But sellers of electric appliances have been left out in the cold.

"Most new apartment buildings are well equipped to handle cold weather so not too many people need heaters," said a slightly disappointed salesman in Shanghai.

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Zhu Lingqing contributed to this story.