Scientists Invent Colorful Paints That Keep Buildings Cool & Warm All Year Round

In October last year, researchers at Purdue University improved the institution’s iteration of the world’s whitest paint—coming up with a new formula that reflects up to 97.1% of the sun’s rays that could be used to cool down buildings, vehicles, and even rockets.

Now, scientists at Stanford University have unveiled a newly-invented batch of paints, this time in a wider array of hues, ranging from orange to yellow, blue, and white. These colors help minimize the need for both heating and air-conditioning, significantly reducing energy costs.

According to the team, the creation of these unique paints comes at a time when energy consumption for heating and cooling accounts for approximately 13% of global energy use and contributes about 11% of greenhouse gas emissions.

The researchers’ goal was to tackle this issue head-on by designing a type of colorant that could help regulate indoor temperatures, making buildings cooler in summer and warmer in winter as the seasons change throughout the year.

In test experiments, the use of the new colors led to a 36% reduction in energy usage for heating in cold conditions and nearly 21% less energy needed for cooling in warm conditions.

Conveniently, these paints can be applied to both interior and exterior surfaces. For example, to keep heat out during hot weather, the pigments can be applied to external walls and roofs.

Most intriguingly, the paint has a two-layer composition: an infrared reflective bottom layer utilizing aluminum flakes and an ultrathin, infrared transparent upper layer using inorganic nanoparticles.

This dual-layer design allows the paint to reflect a substantial portion of high mid-infrared light, which is responsible for a significant amount of heat absorption by surfaces.

Furthermore, the aesthetics of the paint have also been taken into consideration. Unlike current low-emissivity paints that often come in white, metallic silver, or gray colors, these dyes offer a wide range of colors due to the infrared transparent upper layer.

This means that energy-efficient buildings no longer have to sacrifice their appearance for functionality and can be extended to cover trucks and train cars used for transporting goods that require cooling.

Notably, both layers of the paint are water-repellent, which enhances their stability in humid environments. Cleaning painted surfaces is straightforward, requiring only a wet cloth or water flushing.

Even when subjected to extreme conditions, such as high temperatures, low temperatures, and acidic environments, the paints’ performance and appearance remain unaffected.

Going forward, the scientists will continue to work on refining the paint formulations for practical uses in the real world. The team is looking into trading the organic solutions currently used for water-based solutions, which would make the hues more eco-friendly and commercially viable.

[via New Atlas and Nature World News, cover image via Yucan Peng / Stanford University]