Scientists in Singapore have created a special type of white paint. It keeps buildings cool by working like humans sweating. This new “sweating paint” is a cement-based formula. It doesn’t just reflect sunlight. It also stores water and slowly releases it to cool surfaces through evaporation.
This sweating paint uses three cooling methods together. These are radiative cooling, solar reflection, and evaporative cooling. Together, they help reduce indoor temperatures during hot, humid weather. This innovation could reduce the need for air conditioning. It could also help lower energy use in crowded cities.
Researchers at Nanyang Technological University in Singapore developed this new cooling paint. Material scientist Li Hong said, “The key is passive cooling. It works without energy input, no electricity, no mechanical systems. Just physics.” The sweating paint follows this same principle.
Most cooling paints used today keep water out. That is because moisture can damage walls. But in this case, scientists wanted to do the opposite. They designed the paint with a porous structure. This allows it to hold water. When the water evaporates, it cools the surface. That is just like sweat cools our bodies. That is why they call it sweating paint.
The research team tested the paint in real conditions. They painted three small houses in Singapore. One house had regular white paint. Another had commercial cooling paint. The third had their new sweating paint formula. After two years of Singapore’s heat and humidity, only one paint stayed bright white. Co-author Jipeng Fei said, “Our paint was still white. The other paints had turned yellow.”
White reflects sunlight better than other colours. This helps keep buildings cool. The paint also uses tiny nanoparticles. These make it more reflective and keep the paint strong over time. It reflects between 88 and 92 percent of sunlight, even when wet. It also gives off up to 95 percent of the heat it absorbs. A small amount of polymer and salt helps the paint hold water. It also stops the paint from cracking.
The house with the new formula used 30 to 40 percent less energy for air conditioning compared to the other houses. This showed that sweating paint is not just effective in the lab. It works in the real world.
This is good news for cities like Singapore. The climate there is hot and humid year-round. Humid air holds more heat. This makes it harder for buildings to cool down. That is why air conditioners work so hard. They have to remove both heat and moisture from the air. The new paint helps with both problems. It reflects sunlight and slowly evaporates water to cool buildings naturally.
The paint may also help reduce the “urban heat island” effect. This is a common problem in large cities. Buildings, roads, and other structures absorb and hold heat. This makes the area hotter than the surrounding countryside. Co-author See Wee Koh said, “Singapore has very severe UHI, and so do other regions like the Middle East. Our paint could reduce that heat burden in dense urban environments.”
The energy savings are also important. Koh said, “Around 60 percent of building energy is used for space cooling.” If this new paint can cut that by even 30 percent, it would mean a huge reduction in electricity use and greenhouse gas emissions. This is especially true in warmer parts of the world.
Air conditioning systems push warm air into the streets and use a lot of power. But this paint cools surfaces without creating extra heat. It releases heat as invisible infrared radiation. That heat goes into the atmosphere instead of heating the area around the building.
More cities are looking for green, low-energy solutions. This simple but powerful idea from Singapore shows that sometimes the best solutions come from nature. Scientists copied how our skin sweats to stay cool. They may have found a way to keep homes comfortable without harming the planet. That is the promise of sweating paint.
The study was published in the journal Science. Researchers hope that their work will lead to new products. These products could be used in homes, schools, offices, and other buildings in warm climates. The goal is to help people live comfortably without relying so much on air conditioning.
