The development of smart paints and cooling coatings capable of reducing surface temperatures without the need for electricity is generating great expectations in a context of increasingly intense heat waves and growing pressure on electrical systems.
Companies like SkyCool Systems and international research teams are promoting the application of radiative cooling technologies, a passive solution that promises to significantly reduce air conditioning demand, according to data released by MIT Technology Review.
The principle of radiative cooling
Radiative cooling is based on the natural ability of objects to dissipate accumulated heat during the day. Qiaoqiang Gan, a professor of materials science at King Abdullah University of Science and Technology in Saudi Arabia, explained that car metal roofs cool at night because they transfer heat to the sky, reaching temperatures even lower than the ambient temperature.
This process, known for centuries in cultures of Iran, North Africa, and India, was used to make ice or design reflective roofs that reduced heat in homes. “Radiative cooling is universal; it exists in our daily lives,” Gan emphasized.
The principle involves reflecting most of solar radiation and allowing the remaining heat to escape as infrared radiation through the so-called atmospheric window, a range of wavelengths that is not absorbed by the atmosphere and allows heat to dissipate directly into space.
From photonic films to accessible coatings
The first experiments in 2014 used advanced photonic films to maximize heat dissipation. Today, the sector prioritizes simpler and more robust materials: ceramic roofs, reflective polymers, and films based on nanomaterials.
Startups like SkyCool Systems, Planck Energies, Spacecool, and i2Cool compete in the commercialization of coatings that reflect at least 94% of solar radiation, exceeding 97% in humid tropical climates.
SkyCool Systems explained that their film, applied on panels and roofs, prevents heating under the sun and emits infrared heat to the sky, maintaining cooling throughout the year, day and night.
Applications in buildings and textiles
The implementation of these coatings goes beyond conventional reflective roofs. They have been installed in supermarkets in California and in pavilions like the one at the Expo 2025 in Japan.
The concept also expands to reflective textiles to protect people exposed to extreme heat. Gan noted that experiments are already underway with t-shirts and sportswear to achieve personal passive cooling.
Energy and climate impact
Data shows that the use of these smart paints can keep indoor environments up to 5 °C below ambient temperature without air conditioning.
- As a complement to existing systems, they improve energy efficiency by 10% to 40%.
- As a substitute for air conditioning, they reduce energy consumption by up to 80% or 90%.
- Thermal images show that treated areas reach temperatures up to 35 °C lower than untreated areas.
Limitations and environmental challenges
Performance depends on external factors such as clouds, dust, or pollution, which affect solar reflection and heat transfer. Additionally, many coatings lose reflective capacity after years of exposure.
An additional challenge is the use of fluoropolymers like Teflon: durable and low-cost, but considered “forever chemicals” due to their difficult environmental degradation. The challenge is to maintain technical properties without resorting to these materials.
Experts agree that radiative cooling will not be a standalone solution to climate change nor will it completely replace air conditioning. However, its scalability and low cost make it a key tool for adapting buildings and garments to rising temperatures and the global energy crisis.
