China's rooftop rain: Apartment complex uses mist-spraying system to beat the heat

A rooftop mist-spraying cooling system that lowers building temperatures by dispersing fine water droplets has drawn wide attention after being installed at a high-rise apartment complex in China's central Shanxi Province.

Amid a stretch of record-breaking heat across China, Mao Ning, spokesperson for China's Ministry of Foreign Affairs, shared a video on her X account on Wednesday showing the system in action. "A residential complex in China's Shanxi Province is attracting attention with its 'rooftop rain,'" she wrote.

Mao said the mist cooling system can lower building surface temperatures by 5 to 8 degrees Celsius within minutes.

The video shows more than a dozen streams of fine mist cascading down from the top of an apartment tower dozens of stories tall.

According to India Times, an Indian online outlet, the scene may look like something out of a dystopian film, but the principle behind it is remarkably simple. Fine mist particles sprayed into the air evaporate before reaching the ground, absorbing heat from the surrounding air in the process — the same mechanism by which the human body cools itself through perspiration.

Mist-spraying cooling systems are already common at outdoor restaurants and theme parks, but what makes the Chinese installation stand out is its sheer scale. Rather than simply cooling a terrace, the system uses high-pressure nozzles fitted across an entire high-rise residential complex to cool the air throughout the development. The cooling effect is said to last for several hours.

Because the water droplets are extremely fine, they evaporate almost entirely in hot, dry conditions without wetting the ground or passersby — making the system well-suited to arid climates. In high-humidity environments, however, the slower rate of evaporation reduces its cooling effectiveness.

Some experts have raised concerns about water consumption, but the system's operators say it uses less water than conventional sprinkler methods, making it more efficient.

According to Chinese financial outlet Sina Finance, the system has been installed across all 12 residential buildings in the first phase of an apartment complex in Yuncheng. The total project cost came to 16.5 million yuan ($2.43 million), with more than 1 million yuan invested per building.

A single operation of the system is said to cost more than 10,000 yuan. The installation and operating costs are covered by the property management company, and residents are not charged separately. Operating costs are included in a monthly maintenance fee of around 2.8 yuan per square meter.

Yuncheng's meteorological authorities have designated the complex as a model project for community climate adaptation and are reviewing plans to expand the system citywide.

China has seen a sharp rise in cooling demand as record heatwaves become more frequent. Some areas in the country's northwest are enduring temperatures above 40 degrees Celsius, and the urban heat island effect — where buildings and roads trap heat, pushing city temperatures higher than those in surrounding rural areas — is intensifying.

Local media outlets said that as extreme heat becomes the norm, new cooling technologies are expected to become a common sight across cities in the years ahead.