ZERC founder Lee Heon (blue shirt) with his team mates
In much of Southeast Asia, heat has stopped being a seasonal inconvenience and become an infrastructure problem. Parked cars can hit cabin temperatures of 70 to 90 degrees Celsius within minutes, air-conditioning strains power grids at peak demand, and concrete-heavy cities from Bangkok to Jakarta trap heat well into the night.
ZERC, a deeptech startup spun out of Korea University in November 2022, believes part of the solution could be as simple as a coat of paint. Founded by materials science professor Lee Heon, the company has developed a water-based radiative cooling paint that reflects 96 per cent of sunlight and radiates over 93 per cent of absorbed heat back into space, lowering surface temperatures without consuming any electricity.
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Unlike many competitors that rely on toxic, solvent-based formulations, ZERC’s paint uses polymers, water, and ceramic pigments, eliminating volatile organic compound emissions at the source. The company is targeting rooftops, vehicles, ships, industrial equipment, and even safety helmets, positioning paint as a cheaper, more versatile alternative to radiative cooling panels and films.
We spoke to Lee about ZERC’s Southeast Asia (SEA) strategy, the true economics of the technology, and the obstacles standing between the startup and its first large-scale commercial deployment in the region.
Edited excerpts:
SEA looks like your toughest and most promising market. What’s the actual go-to-market plan? Direct sales, licensing, or partnerships?
We’re keeping all three options open. Our initial strategy is to export the finished product into Southeast Asia, establish its performance and credibility there, and then expand with local partners. Ultimately, we envision local production through licensing agreements with regional paint manufacturers.
SkyCool uses panels, SpaceCool uses film, RadiaCool focuses on EVs. You’ve bet everything on paint. Where might that bet lose?
Paint is the most versatile, commercially applicable format of radiative cooling technology. It has a relatively low manufacturing cost, can be applied easily over very large areas, and works on curved or irregular surfaces where panels and films are more limited. Installation costs are also significantly lower than film.
For these reasons, I believe cooling paint has the potential to dominate the radiative cooling materials market. Its main weakness is that manufacturing cost is still higher than conventional paint, though that additional cost is typically recovered within one to two years through energy savings.
Water-based formulations are often criticised for weaker adhesion and shorter lifespans than solvent-based ones. How did you solve that trade-off?
Water-based paint is more environmentally friendly, but its coating durability is generally inferior to oil- or solvent-based paint. So I expect solvent-based cooling paints to gain market adoption first.
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In the longer term, however, as water-based formulations improve and environmental regulations tighten, I expect water-based radiative cooling paints to become increasingly important.
You claim that the cooling effect can last for more than five years. Has this claim been validated through multi-year field testing in tropical conditions, or is it extrapolated from lab ageing tests?
It’s currently an estimate based on standard accelerated ageing tests. In harsher environments, actual lifespan could be shorter. Put another way: we expect performance comparable to conventional solvent-based exterior paints. If a conventional paint can maintain its coating for five years under a tropical monsoon climate with strong UV exposure, we expect our cooling paint to last just as long, or longer.
Walk us through the actual numbers — cost per square metre versus electricity savings for a mid-sized warehouse roof in Manila or Jakarta.
The paint costs around US$10 per square metre. Incoming sunlight carries over 1,000W/m² of energy; conventional paint reflects only 30 to 80 per cent of it, while ours reflects over 95 per cent. That means our coating absorbs roughly 500-600 watts less solar energy per square metre than conventional paint.
Assuming only half of that reduced heat load translates into lower cooling demand, and that a cooling system runs eight hours a day for 300 days a year, that works out to around 600 kWh of reduced heat load annually. With a cooling system coefficient of performance (COP) of 3, that equates to roughly 200 kWh saved per square metre each year. At about US$0.12 per kWh, that’s approximately US$24 in annual savings per square metre, meaning the paint’s additional cost can potentially be recovered within the first year.
Safety helmets are a strikingly different category from rooftops and ships. Genuine commercial priority, or proof-of-concept?
It’s essentially a proof of concept, though it could bring real benefits to outdoor workers enduring hot conditions. It demonstrates that the technology works not only on large structures, but also on small, irregularly shaped objects directly exposed to sunlight, solving the discomfort of sweat trapped inside a helmet.
Turning smelting slag into a cooling pigment is compelling, but industrial byproducts vary batch to batch. How do you guarantee consistent optical performance?
The slag-based paint, developed with South Korean steel manufacturer POSCO, is primarily a demonstration of sustainability and circularity potential rather than the core of our commercial strategy. In fact, without slag, we can produce a higher-performance radiative cooling paint. It shows how industrial waste can be upcycled into a functional material, rather than defining our product roadmap.
Which country are you targeting first for regulatory approval, and what’s been the biggest bureaucratic surprise?
We haven’t yet obtained certification in Southeast Asia –only in Korea so far. We expect regional requirements to be broadly similar, so we don’t anticipate certification being a major obstacle once we begin expanding in earnest.
EV battery-range preservation requires OEM-level integration, not just aftermarket application. Are you in talks with any EV or fleet manufacturers in the region?
Our initial EV application isn’t passenger cars; we’re testing the paint on electric bus roofs, running joint experiments with a global automobile manufacturer, with very promising results so far. We haven’t yet discussed this application with Southeast Asian EV or fleet companies, but we’d be very interested in joint testing with regional partners.
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What’s the single biggest obstacle to ZERC’s first large-scale commercial deployment in Southeast Asia?
To launch large-scale projects there, our first priorities are securing sufficient funding and expanding our team. We’ll also need reliable local distribution and business partners. Manufacturing, however, isn’t likely to be the bottleneck; our facility in Ulsan, Korea, can already produce up to around five tonnes a day, and scaling further by using existing paint manufacturing facilities in Korea or Southeast Asia should be relatively straightforward. Our biggest immediate challenge is securing the funding, people, and local partners needed to accelerate commercialisation in the region.
The post No fans, no fridges, just paint: ZERC’s founder on cracking SEA’s cooling crisis appeared first on e27.