# Behind the sweating towers of Shanxi

By [Brandon Donnelly](https://brandondonnelly.com) · 2026-07-03

china, evaporative-cooling, building-systems, cooling, osaka, japan, cooling-mist, tech

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A residential community in China's Shanxi province has been in the news recently for a cooling system that sprays mist from its rooftops to lower the surrounding surface temperatures. [Here's a video](https://x.com/SpoxCHN_MaoNing/status/2072308419835641896?s=20) in case you missed it.

As I understand it, this evaporative cooling technique can lower nearby surface temperatures by 5°C to 8°C within minutes, and it uses significantly less electricity than air conditioning.

This, by the way, is the same scientific principle behind how sweat cools human skin. We sweat, the sweat then evaporates, and in the process it helps to lower our body temperature.

But the obvious question here is: Doesn't this waste a bunch of water?

Generally, these systems tend to rely on (1) very fine mists of water (so as little water as is necessary) and (2) collected rainwater and/or recycled greywater. The general idea is to just lower surface temperatures so that less air conditioning is needed.

Next, it becomes a question of electricity saved vs. water consumed. A [study](https://www.researchgate.net/publication/316997516_Effect_of_the_Evaporative_Cooling_Techniques_by_Spraying_Mist_Water_on_Reducing_Urban_Heat_Flux_and_Saving_Energy_in_an_Apartment_House) done on a 5-storey apartment building in Osaka found that outdoor misting reduced the building's cooling loads by an average of 36%, and from a financial standpoint, the value of the electricity saved was greater than the cost of the water consumed.

Importantly, it also helped reduce the overall urban heat island effect in the area. The amount of waste heat trapped in the nearby city streets decreased by over 60%.

Hotter streets are a byproduct of air conditioning because the cooling process effectively sucks heat out of interior spaces and transfers it outside. Misting counteracts that and also reduces peak AC loads.

So, as wild as these sweating towers may appear online, there is some logic behind them.

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_Cover photo via_ [_this Twitter post_](https://x.com/SpoxCHN_MaoNing/status/2072308419835641896?s=20)

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*Originally published on [Brandon Donnelly](https://brandondonnelly.com/behind-the-sweating-towers-of-shanxi)*