HÀ NỘI – A handmade cooling device – one of the best selling products for low-income earners in cities can cause negative impacts on users’ health and household appliances, engineers and health experts warns.

The handmade cooling devices became popular in big cities like HCM City and Hà Nội last summer when Dương Ngọc Mỹ, a senior student studying automobiles at the Hà Nội University of Industry, developed the invention to cope with rising temperatures.

The device comprises a mini fan, a 60ml water bottle, a piece of foam and uses a USB connection for power.

From a 62sq.cm rectangular box, Mỹ makes an air conditioner equivalent to 2000BTU. A regular air conditioner sold on the market ranges from between 9,000 to 12,000BTU. Two kilos of ice (VND6,000 or $0.27) is enough to produce cool air for a 10sq.m room for four or five hours. In practice, this can reduce room temperature by around six or seven degrees Celsius.

Following Mỹ’s example, people rushed to make similar “air-conditioners” at home or buy them at prices ranging from VNĐ 100,000 ($4.50) to VNĐ 400,000 ($18.00).

In HCM City, citizens have been using a styrofoam box, mini fan and L-shaped waterpipe to make a similar air cooling device. Such devices can cost between VNĐ 200,000 ($9.00) and VNĐ 450,000 ($20.00) to manufacture.

Dr Trần Văn Thịnh from Hà Nội University of Science and Technology told Khoa học và Đời sống (Science and Life) newspaper that handmade cooling devices are simple to make but could pose risks to the user’s health.

The device works on a similar principal to that of steam fans, which were popular for years, he said.

However, when using handmade cooling devices, users cannot adjust the temperature.

More importantly, Thịnh said the ice-run devices have the potential to spread viruses and bacteria if the frozen water used is contaminated. Viruses and bacteria are major contributers to summer diseases, particularly among young children.

He added that uncontrolled humidity released from the devices could also damage electrical equipment and circuits.

However, students and low-income earners who have been quick to adopt the handmade cooling devices said that they were satisfied with their devices.

At least, they helped relieve summer heat which is so often the bane of many city-dwellers’ lives. -- VNS