ZERC Launches Water-Based Paint to Radatively Cool Roofs, Vehicles, and Helmets

In the intense heat of Southeast Asia, a stationary vehicle can quickly become uninhabitable. Cabin temperatures frequently surge to 70 or 90 degrees Celsius, meaning the initial blast of air conditioning shifts from a luxury to a physiological necessity.

However, air conditioning presents a significant paradox; it cools interior spaces while expelling heat outdoors and consuming substantial electricity. Across cities such as Singapore, Bangkok, Manila, Jakarta, and Ho Chi Minh City, this cycle intensifies peak power demand and exacerbates the urban heat island effect, where concrete, asphalt, and glass retain warmth well after sunset.

Korean deep-tech startup ZERC believes the solution to part of this challenge is as straightforward as paint.

Founded in November 2022 as a faculty spinoff from Korea University, ZERC is commercializing a water-based radiative cooling paint applicable to roofs, vehicles, ships, industrial machinery, and even safety helmets. The company was established by Lee Heon, a professor in Korea University’s Department of Materials Science and Engineering, who has dedicated his career to developing materials that lower surface temperatures without electricity consumption.

“We founded the company and are committed to our research to deliver a practical breakthrough for the climate crisis and energy challenges through electricity-free temperature reduction technology,” Lee stated.

The Mechanics of Radiative Cooling

The concept of radiative cooling is not entirely novel, but its commercial viability has surged as rising global temperatures place increasing strain on electrical grids.

The fundamental principle is straightforward: a material reflects the majority of incoming solar radiation, preventing surfaces from absorbing heat. Simultaneously, it emits thermal radiation through what scientists refer to as the “atmospheric window” — a band of infrared wavelengths capable of passing through the atmosphere and escaping into outer space.

In practical terms, the surface achieves cooling without the need for fans, compressors, refrigerants, or electrical power.

ZERC reports that its water-based paint reflects 96 percent of sunlight when applied at a thickness of 150 micrometres, roughly equivalent to the width of a human hair. Additionally, it radiates more than 93 percent of heat into space through the atmospheric window. Testing indicates the paint maintains a surface temperature approximately 4 degrees Celsius lower than standard water-based alternatives.

The company claims the cooling effect can persist for over five years, and that the initial installation cost can be recouped through electricity savings within a single summer season. The paint is also asserted to resist rain, wind, and sunlight — a crucial requirement for transitioning beyond controlled demonstrations into construction sites, logistics fleets, factories, and public infrastructure.

For the hot and humid climate of Southeast Asia, where cooling represents a primary driver of energy consumption, this technology stands to generate significant interest among building owners and municipal authorities. The International Energy Agency has issued warnings about the rapid growth in space cooling demand, particularly in emerging economies. In this region, rising incomes, urbanization, and increasingly frequent heatwaves are transforming cooling into both a public health imperative and an energy security challenge.

The Importance of a Water-Based Formulation

The central claim behind ZERC’s technology is that it not only cools surfaces effectively but does so using a water-based paint format.

According to Lee, paint-based solutions are increasingly regarded as more practical than films or panels because they can be applied using rollers or spray equipment. Films are often difficult to install on curved surfaces, irregular structures, or expansive areas. In contrast, paint integrates seamlessly with existing construction and maintenance workflows.

The challenge, however, is that many radiative cooling paints have traditionally relied on organic solvents such as toluene. While these solvents facilitate the application of thick paint and can lower costs, they evaporate during application and drying, releasing volatile organic compounds (VOCs). VOCs are hazardous air pollutants, and some pose serious health risks.

ZERC states it has overcome this hurdle by developing a proprietary formulation that combines polymers, water, and ceramic pigments in place of toluene. A polymer serves as a binder, helping pigment particles adhere firmly to the painted surface, while the ceramic pigments provide the necessary optical properties for sunlight reflection and thermal radiation.

“Field painting companies are highly sensitive to price, ease of application, and eco-friendliness, which is why they have used toluene — despite its toxicity — until now,” Lee explained. “We have instead eliminated VOC emissions at the source through a technology that combines polymers, water, and ceramic pigments in place of toluene.”

This distinction could prove commercially significant. Across Southeast Asia, governments are tightening environmental and workplace safety standards, yet the construction and industrial maintenance sectors remain highly cost-sensitive. A cooling paint that requires specialized handling, releases hazardous fumes, or disrupts standard application methods would face a steeper path to adoption.

Applications From Roofs to Helmets

ZERC identifies applications wherever paint can be utilized: building exteriors, roofs, vehicles, ships, and industrial equipment. In tropical regions, roofs represent the clearest use case. Warehouses, factories, schools, bus depots, and low-rise residential buildings frequently absorb vast amounts of solar heat through their rooftops, raising indoor temperatures and heightening the need for mechanical cooling.

Vehicles represent another primary target. Delivery vans, buses, passenger cars, and electric vehicles all face significant heat-management challenges. For EVs specifically, reducing cabin cooling loads can help preserve battery range — a critical concern in hot climates.

An additional, immediate human application lies in worker protection. ZERC is exploring the use of radiative cooling paint on safety helmets for outdoor workers, including those in construction, logistics, ports, and public works.

“If radiative cooling paint is applied to workers’ safety helmets during summer, it can significantly improve thermal comfort,” Lee noted. “Workers must wear safety helmets for physical protection, but the paint can directly address the issues of sweat and discomfort trapped inside the helmet. I believe this is one way advanced science can assist vulnerable populations.”

This point is especially relevant in Southeast Asia, where outdoor workers are increasingly subjected to heat stress. As heatwaves become more frequent, employers and regulators face pressure to mitigate risk without impeding essential work. Passive cooling tools, provided they are affordable and durable, could become a vital component of a broader worker-safety framework.

The Expanding Climate-Tech Race

ZERC is entering a market that has already attracted both startups and major industrial players. Market research firm Spherical Insights projects the radiative cooling market will grow from US$35.8 billion in 2023 to US$87.7 billion by 2033, representing an average annual growth rate of over 9 percent.

In the United States, SkyCool Systems has demonstrated electricity savings by applying radiative cooling panels to supermarket HVAC systems. RadiaCool has focused on reducing cooling loads in electric vehicles. Japan’s SpaceCool has installed cooling film on buildings, including for the Osaka Expo.

These companies demonstrate that the sector is advancing beyond laboratory research. However, they also highlight the diverse approaches within radiative cooling: panels, films, coatings, and paints. ZERC’s wager is that a water-based paint will succeed in environments where low-friction installation, worker safety, and compatibility with existing surfaces hold greater importance than highly engineered hardware.

The startup is also exploring industrial circularity. Lee recently collaborated with POSCO to develop a radiative cooling paint that recycles slag, a byproduct generated during the smelting of iron ore to produce iron. If commercialized, this approach could provide the technology with an additional sustainability dimension by transforming industrial waste into a cooling material.

The larger question remains whether ZERC can transition from scientific performance to commercial reliability at scale. Paint must withstand weather, pollution, abrasion, uneven application, and years of exposure. Customers will also compare it against conventional reflective coatings, insulation, roof retrofits, and traditional cooling systems.

Nevertheless, the timing is highly favorable. Across much of Asia, heat is no longer merely a seasonal inconvenience; it is evolving into an infrastructure problem, a labor issue, and a significant financial burden. If ZERC can prove that its water-based radiative cooling paint performs reliably under real-world conditions, it could find demand not only in Korea but across the hotter, fast-urbanizing markets of Southeast Asia.

As Lee articulated, the objective is to move university deep-tech research “beyond papers and patents” toward resolving real-world challenges in industry, energy savings, and carbon reduction. In a warming region, that ambition will be tested not in the laboratory, but under the sun.

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