Full report
A cooler window is an appealing idea. A window that helps a building shed heat while still admitting daylight is more interesting still. For the film industry, the important question is not simply whether a laboratory sample becomes cooler. It is what kind of window that sample could eventually become.
Two August 2026 papers investigate heat arriving from a window’s surroundings, not just sunlight. These are research developments, not product launches.
A window looks sideways
The August 13 Small paper describes transparent organosilica designed to emit thermal radiation selectively at 8–13 micrometers. UCLA researchers report a surface roughly 0.5°C cooler than a broadband emitter in field testing—not a room-temperature reduction.
Their ambigel is a porous network dried under ambient conditions. This is materials research, not a specification for an adhesive tint roll. The accessible abstract does not establish an installation system or service life.
The August 21 Advanced Functional Materials paper takes a directional approach: partially silver-coated PET microprisms reflect ground-originating thermal radiation while admitting daylight and emitting heat skyward.
What the experiments actually establish
Its November 2025 outdoor test monitored enclosed air behind small, south-facing samples with matched solar transmission—not occupied rooms. Annual building-energy results were modeled.
The results are not a temperature leaderboard: surface measurements and enclosed-air measurements under different conditions are not interchangeable.
Daylight is not the same as a clear view
The authors distinguish daylight from image clarity: microprisms can distort the view. Optical refinement and surface-contamination management remain development needs.
This distinction is commercially important. A project brief should say whether people need comfortable daylight, an undistorted outlook, or both. Research aimed at one function should not automatically be sold as evidence for the other. Installers need a defined use case before a promising material can become a convincing recommendation.
The next useful test is a building test
Berkeley Lab’s FLEXLAB offers an instructive example of the development process, separate from these two papers. Its 2024 case study describes work with Lucent Optics on three-dimensional printed window-film prototypes. Testing included light-scattering measurements and full-scale assessment of heating and cooling, lighting, visual comfort and thermal comfort at two solar-angle conditions. One prototype performed unexpectedly well at solar control, prompting the company to focus subsequent development there rather than on light redirection.
That example points to a constructive next step: test a proposed benefit alongside the other things a window must do. A cooler specimen is worth investigating. Evidence about daylight, glare and the energy used to keep an occupied space comfortable makes that result more useful to a specifier. That is a useful development milestone: a result that changes the design decision, rather than merely adding a striking number to a brochure.
Why the research matters without a launch
A September 2024 National Renewable Energy Laboratory report provides another reminder about scale. Its modeling of solar-control films evaluated entire glazing systems and buildings across weather and load conditions. Reducing solar heat gain can help cooling while also reducing useful winter heat gain. The report therefore examined when and where energy savings occur, rather than assigning one saving to every installation. This older work does not validate either 2026 prototype.
The report also separates energy analysis from other reasons people choose film, including glare, visual comfort, privacy and appearance. Existing solar-control films can modify the performance of glazing without replacing the window. Future cooling materials need an equally understandable application: what they add to the building, how they integrate with its glass and which customer benefit the evidence supports. For a property owner, the starting point remains the room’s problem. A bright but uncomfortable office and a space needing privacy can justify different products; an energy-only result should not erase those differences.
Reporting note
TintNews reviewed the full microprism paper, the organosilica paper’s public abstract, and two laboratory publications. We did not conduct tests or interviews. Commercial availability, installed durability and whole-building performance of these research materials were not independently established.
Sources & reporting notes
- Sky-Directional Radiative Cooling Meta-Films for Daylighting Windows Advanced Functional Materials · Source dated August 21, 2026
- Mesoporous Organosilica-Based Infrared Metamaterials for Radiative Cooling of Windows Small · Source dated August 13, 2026
- Improving Window Films to Reduce Cooling Loads and Glare Lawrence Berkeley National Laboratory
- End-Use Savings Shapes Measure Documentation: Window Film National Renewable Energy Laboratory
This article is an original, AI-assisted summary of the sources above. It does not claim firsthand reporting or independent product testing. Our editorial standards · Corrections policy