July 11, 2025, 4:04 pm | Read time: 3 minutes
Air conditioners are gradually becoming more common here as well—but they consume vast amounts of energy. A newly developed paint might offer a solution. It can cool entire buildings without using electricity. What’s behind this innovation?
An international team of scientists has developed an innovative cement-based paint that can cool buildings passively. It relies on physical processes and requires no additional energy input. Cooling by several degrees Celsius is possible. Initial tests already show impressive results.
Cooling Buildings with Paint – An Alternative to Air Conditioners?
In many regions worldwide, traditional cooling systems are increasingly reaching their limits—either due to high costs, lack of efficiency, or negative environmental impacts. Even in Germany, the demand for air conditioners is rising, especially during the hot summer months. The paint named CCP-30 could offer a sustainable alternative in the future.
A study published in June 2025 in the journal Science describes the development of an innovative passive cooling paint that combines both radiative and evaporative cooling. This paint is based on a modified cement-based structure with nanoparticles that enable high solar reflection, minimal heat conduction, and effective water evaporation. The paint can also absorb water from the environment and maintain its cooling performance even in humid weather.
How the Innovative Paint Works to Cool Buildings
Two physical effects create the special cooling effect: First, CCP-30 uses “radiative cooling,” where heat is emitted to the surroundings as infrared radiation. Second, “evaporative cooling” is employed: Stored water evaporates and removes heat from the building. Essentially, this is a similar effect to sweating. This combination makes the paint particularly efficient in areas with high humidity.
Central to this is a sponge-like material inside the paint: Calcium silicate hydrate with numerous micro-pores can store water without swelling or disintegrating. Additionally, CCP-30 contains reflective particles of barium sulfate that almost completely reflect sunlight. Polyvinyl alcohol and lithium chloride serve as water binders and enhance the evaporation effect.
Self-Repairing Properties and High Stability
The paint not only impresses with its cooling performance but also with its durability. Small damages in the coating can self-repair, similar to concrete that hardens under moisture. If the surface is damaged, it absorbs moisture from the air and automatically seals fine cracks. Even long-term, the structure remains stable, without chipping or swelling.
Successful Tests Under Real Conditions
In field tests in Singapore, the paint showed significantly better cooling performance compared to commercially available white paints. Pilot projects demonstrated consistent energy savings under various weather conditions. Theoretical models supported these results.
CCP-30 was tested under real conditions: Three identical houses were painted with different paints—with conventional white paint, reflective special paint, and CCP-30. The result was clear: In the CCP-30 house, it was up to seven degrees cooler during the day, and the energy consumption of the air conditioner decreased by up to 40 percent—within just one month.
And even long-term, the coating showed no losses: Neither strong sunlight nor high humidity could affect the paint. However, CCP-30 is not yet available on the market. Researchers expect this to change in the coming years.
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Environmentally Friendly, Cost-Effective, and Future-Proof
According to the scientists, the material is inexpensive to produce, mechanically robust, and can be processed using known cement techniques. From an ecological perspective, the innovation is also convincing: Although comparatively many substances are used in production, significant CO₂ savings can be achieved long-term due to lower energy consumption.