A University of Colorado Boulder team has developed a transparent silicone material designed to slow heat transfer through windows. Called MOCHI, it combines a network of nanoscale, air-filled pores with high visible transparency. The researchers report promising material properties, but MOCHI is not yet available to consumers, and no occupied-building energy savings have been established.
What is MOCHI window insulation?
MOCHI stands for Mesoporous Optically Clear Heat Insulator. Developed by a University of Colorado Boulder team led by physics professor Ivan Smalyukh, it is a silicone-based material with a network of tiny pores. The university says air accounts for more than 90% of its volume. The study describes structural features smaller than 50 nanometers.
The approach addresses a familiar building-envelope tradeoff: walls can use thick insulation, but windows must let in light and preserve the view. Conventional aerogels can trap air, yet their structure may scatter light and make them look cloudy. MOCHI is designed to limit that scattering; this is a research objective, not proof that it outperforms every commercial window or film.
How does the material slow heat transfer?
The university describes a process in which surfactants template channels in silicone. During processing, surfactants and solvents are replaced with air, leaving a porous silicone network. According to CU Boulder, the small pores restrict gas-molecule collisions, reducing one route for heat transfer through the material.
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- Save on energy costs during cold weather months. Duck Max Strength shrink window film is puncture-resistant and two times thicker than standard window kits to create an airtight seal inside your home to block drafts and cold weather
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- Tools needed: scissors and hair dryer. For best results apply window films indoors on clean and dry surfaces, including painted or finished wood, aluminum or vinyl
- After installation, crystal clear and transparent window film is easy to see through. Once season is over, the window kit removes easily
- Window Kit includes 1, 62" x 210" roll of shrink film and 1, 0.5" x 84' foot roll of tape; Can insulate up to 5 standard sized 3' x 5' windows
That mechanism does not mean a window treated with MOCHI would eliminate heat loss. Whole-window performance also depends on the glazing, frame, installation, weather, and building conditions. The published findings concern the material, not a finished, field-tested window system.
What performance did the 2025 study report?
Amit Bhardwaj and coauthors reported in Science on December 11, 2025, that MOCHI achieved visible-range optical transparency greater than 99% and thermal conductivity of approximately 10 milliwatts per kelvin per meter (0.010 W/(m·K)). The work describes flexible films reaching square-meter dimensions and slabs several centimeters thick. These are material-scale results, not percentages of energy saved in a house.
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- Designed for interior use on windows
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CU Boulder separately reports that the material reflects about 0.2% of incoming light. That is the university’s reflection figure; it is not interchangeable with the paper’s greater-than-99% visible-transparency measure.
Could MOCHI reduce a building’s energy use?
Better insulation at windows could, in principle, reduce heat transfer while retaining daylight and a view. But the available published findings do not give a quantified energy-savings result for MOCHI in occupied buildings, so there is no supported household savings percentage or bill estimate to apply.
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- If you want to open your windows in the warmer months, you'll need to take it off. Otherwise, sunlight and normal stress can also make the tape fail eventually. For a good seal, it's probably best to re-apply them every year.
The Science paper identifies possible uses including transparent thermal barriers in insulated glass units, square-meter-scale window retrofits, and unconcentrated solar thermal energy harvesting. These are proposed applications, not installed products or demonstrated building outcomes.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.Can homeowners buy or install MOCHI now?
No. CU Boulder says MOCHI is currently made in the lab and is not available to consumers. The university describes production as time-intensive, and the paper identifies scale-up as a challenge for mesoporous materials intended for building envelopes. The sources do not establish a launch date, installed cost, long-term weathering performance, or a current manufacturing partner.
Rank #4
- Save on energy costs during cold weather months. This rolled window kit creates an airtight seal inside your home to block drafts and cold weather
- Easy-to-install roll of shrink film means no measuring needed - once applied, cut film to size
- Tools needed: scissors and hair dryer. For best results apply window films indoors on clean and dry surfaces, including painted or finished wood, aluminum or vinyl
- After installation, crystal clear and transparent window film is easy to see through. Once season is over, the window kit removes easily
- Window Kit includes 3, 62" x 210" rolls of shrink film and 3, 0.5" x 54' foot rolls of tape; Can insulate up to 15 standard sized 3' x 5' windows
MOCHI is also distinct from a transparent cellulose aerogel described in a separate 2018 CU Boulder story. That earlier material used cellulose derived from brewery waste; it is not the silicone-based MOCHI discussed here, and its exploratory commercial discussions do not establish a current MOCHI partnership.
Quick Recap
Best Value
- Save on energy costs during cold weather months. Duck Max Strength shrink window film is puncture-resistant and two times thicker than standard window kits to create an airtight seal inside your home to block drafts and cold weather
- Easy-to-install roll of shrink film means no measuring needed - once applied, cut film to size
- Tools needed: scissors and hair dryer. For best results apply window films indoors on clean and dry surfaces, including painted or finished wood, aluminum or vinyl
- After installation, crystal clear and transparent window film is easy to see through. Once season is over, the window kit removes easily
- Window Kit includes 2, 62" x 210" roll of shrink film and 2, 0.5" x 54' foot rolls of tape; Can insulate up to 10 standard sized 3' x 5' windows
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