Can passive radiative cooling actually lower costs while reducing environmental harm?
Yes, several passive radiative cooling materials are designed to be both low-cost and low-impact. A water-based paint formulation [1] uses glass bubbles and a polymer powder, avoiding organic solvents that release volatile organic compounds (VOCs). This makes it safer, cheaper, and more scalable than solvent-based alternatives, while still achieving 90% solar reflectance and 95% thermal emissivity. Similarly, a hierarchically structured PMMA (polymethyl methacrylate) film [6] is made from a common, inexpensive plastic and can cool surfaces by 6-9°C during midday with an average cooling power of ~85 W/m², offering a low-cost route to all-day cooling.
Scalable manufacturing is key to keeping costs down. A woven metafabric [5] produced through standard industrial textile routes achieves 94.5% emissivity and 92.4% solar reflectivity, and in tests cooled a person by ~4.8°C compared to cotton. The authors explicitly highlight its cost-effectiveness and high performance for commercial clothing. A cellular ceramic [3] with 99.6% solar reflectivity and >130 W/m² cooling power at noon is also noted for its weather resistance and mechanical robustness, which reduce maintenance costs over time.
Does it work as well in real cities as in the lab?
Not exactly — real-world conditions can reduce performance significantly. A city-scale study in Xi'an, China [2] found that when you account for how buildings shade each other, the cooling power drops by 14.7% for an ideal broadband surface and 47.1% for an ideal selective surface. This means that while lab tests show impressive results, actual energy savings and carbon reductions (0.52 gCO₂/m²·h from roofs, 0.16 gCO₂/m²·h from walls) are more modest. The study emphasizes that building deployment is often ignored, leading to overestimates of cooling benefit.
Climate also matters. The water-based paint [1] showed that its daytime cooling power could range from near zero to 100 W/m² depending on the ambient temperature reference, highlighting that performance varies with local conditions. The PMMA film [6] still achieved ~5.5°C cooling even in hot, humid climates (930 W/m² solar intensity, 64% relative humidity), suggesting it is robust but not universal. So, while the technology can reduce environmental impact without raising costs, its effectiveness depends on careful siting and realistic expectations.
Will these materials last long enough to be worth the investment?
Durability is a strong point for several designs, which helps keep long-term costs low. The cellular ceramic [3] is explicitly described as having weather resistance, mechanical robustness, and the ability to depress the Leidenfrost effect (a heat-transfer phenomenon), making it suitable for building construction. The transparent wood biocomposite [4] uses ZnO nanoparticles and thiol-ene polymerization to improve mechanical resilience, and it lowered silicon substrate temperatures by 6-7°C under direct sunlight, showing potential for protecting solar cells. The metafabric [5] also boasts mechanical strength, waterproofness, and breathability, which are essential for clothing that must withstand washing and wear.
These durability features mean that the materials are less likely to need replacement, reducing both cost and waste over time. The PMMA film [6] and water-based paint [1] are also designed for ease of application and scalability, further lowering barriers to adoption. Across the studies, the emphasis on practical, long-lasting materials suggests that the upfront investment can be recouped through energy savings and reduced maintenance.
About These Sources
This answer is built on 6 peer-reviewed studies — published from 2021 to 2025, 2 from 2024 or later, 5 in Q1 journals, collectively cited 2,213 times — selected as the most relevant from 6 studies that passed quality screening, drawn from 42 papers retrieved from a database of over 500 million.
Sources used in this answer
Radiative Cooling Potential of a Water-Based Paint Formulation under Realistic Application Conditions
A water-based paint with 90% solar reflectance and 95% thermal emissivity avoids VOCs, is cost-effective, and shows daytime cooling power up to 100 W/m², but performance varies greatly with ambient temperature reference.
Cooling benefit of implementing radiative cooling on a city-scale
City-scale modeling in Xi'an shows building deployment reduces radiative cooling power by 14.7-47.1%, with carbon reductions of 0.52 gCO₂/m²·h from roofs and 0.16 gCO₂/m²·h from walls.
Hierarchically structured passive radiative cooling ceramic with high solar reflectivity
A cellular ceramic achieves 99.6% solar reflectivity and >130 W/m² cooling power at noon, with weather resistance and mechanical robustness for building construction.
Transparent Wood for Passive Radiative Cooling of Solar Absorbers
Transparent wood biocomposite coatings with ZnO nanoparticles lower silicon substrate temperature by 6-7°C under direct sunlight, offering a bio-based, cost-effective cooling alternative.
Hierarchical-morphology metafabric for scalable passive daytime radiative cooling
A woven metafabric with 94.5% emissivity and 92.4% reflectivity, made via scalable textile routes, cools a person ~4.8°C below cotton, with mechanical strength and waterproofness.
A structural polymer for highly efficient all-day passive radiative cooling
A hierarchically porous PMMA film achieves 0.95 solar reflectance and 0.98 thermal emittance, cooling 6-9°C during midday with ~85 W/m² average cooling power, even in hot, humid climates.