Sep 26, Kathmandu - China has started mass-producing a new “super-cooling” coating designed to reduce heat absorbed by building walls during hot weather, according to reports.

The coating can lower the surface temperature of walls by up to about 25°C compared with conventional coatings. It requires no electricity, water or refrigerant to operate.

The technology uses passive radiative cooling. It reflects much of the sunlight that hits a surface while helping release accumulated heat as infrared radiation, potentially reducing the amount of heat entering a building.

The coating was tested for around six months in real-world conditions at a petrochemical plant in Hainan province, southern China. Following the trial, production has moved from the laboratory to industrial scale.

The reported 25°C reduction refers to the exterior surface temperature—not a 25°C drop in indoor room temperature. The effect indoors would depend on factors such as building design, insulation, ventilation, weather and how much of the building is coated.

If the coating proves affordable and durable, it could help reduce air-conditioning use and electricity consumption in homes, schools, hospitals and industrial buildings. Further testing is needed to assess its cost, long-term performance and effectiveness in different climates.