Innovation Signal 54 (2026) | 2 September 2026
Surfaces that cool without electricity are becoming easier to use
Short note, about 5 minutes to read.
What happened
Materials that can help keep surfaces cool without using electricity are not new. What is changing is how easily they could fit into everyday use.
The approach works by reflecting sunlight and allowing heat to escape from the surface (passive radiative cooling). Researchers are now tackling some of the practical problems that have limited where these materials can be used.
Researchers led by City University of Hong Kong have demonstrated coloured cooling coatings that still reflect most incoming sunlight. During outdoor testing, the material cooled as much as 9°C below the surrounding temperature. This matters because effective cooling surfaces have often been restricted in the colours they can use.
Separately, researchers at Kongju National University and Jeonbuk National University developed a cooling paint that can be sprayed onto surfaces and continued to work after outdoor exposure.
Researchers at Kumoh National Institute of Technology have taken another approach: a flexible cooling patch that can be attached, removed and used again.
Together, the developments suggest that researchers are moving beyond simply making surfaces cooler towards making passive cooling easier to fit into the real world.
Why this matters
Most cooling today depends on powered equipment such as air conditioners.
Passive cooling offers another possibility. Roofs, walls and other exposed surfaces could help keep themselves cooler before powered equipment has to remove the remaining heat.
But cooling performance alone is not enough. Materials also need to look acceptable, be easy to apply and withstand everyday use.
The recent research suggests that some of those practical compromises are beginning to weaken.
Who should care
- Cooling and air-conditioning companies
- Building owners and operators
- Roofing, paint and surface-material manufacturers
- Architects and building designers
- Companies managing heat in equipment and facilities
- Energy-efficiency researchers
- Investors tracking emerging cooling technologies
What could change over the next 2 to 3 years
The next step will be combining more of these characteristics in the same material.
Researchers will also need to test larger surfaces for longer periods and across different climates.
More convincing evidence would show that these materials can remain effective while becoming easier and cheaper to manufacture, install and maintain.
What might block this
These materials will not work equally well everywhere. Weather, climate, dirt and physical wear can all affect performance.
Cost and manufacturing at scale will also matter, particularly if the materials have to survive years of outdoor use.
And passive cooling is unlikely to remove the need for air conditioning in many situations. Its value may instead be in reducing how much cooling powered equipment has to provide.
Why I am sharing this
Cooling has traditionally been something done mainly by equipment.
What is interesting about this research is the possibility that the surfaces around us could increasingly do part of that job themselves.
If cooling materials become easier to colour, apply and install, cooling could gradually become a property of the surface as well as a function of the machine.
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Archive Tags
Cooling · Passive Cooling · Radiative Cooling · Surface Materials