Chasing the dream of transparent insulation, researchers hit on a solution: high-tech “bubble wrap”

It’s nearly winter in the Northern hemisphere. For many that means drafty windows that waste energy and keep you from being cozy inside your home. Some turn to clear plastic shrink-wrap insulation kits. But researchers from the University of Colorado Boulder have a more high-tech, long-lasting solution for insulating windows without obstructing the view.

They have made a material that lets 99% of light through while blocking 10 times as much heat as conventional windows. The researchers can make the material as flexible square-meter-sized films that could be applied to existing windows, as well as slabs that are multiple centimeters thick made at the square-meter scale.

The durable material should last for 20 years, the team says. Windows increase the energy use of the built environment. Buildings today consume about 40% of all energy generated worldwide.

And over a quarter of a building’s energy is lost through today’s glass windows. In the winter they let heat out, while in the summer they let the sun’s heat in. “To block heat exchange, you can put a lot of insulation in your walls, but windows need to be transparent,” said Ivan Smalyukh, a professor of physics at CU Boulder.

“Finding insulators that are transparent is really challenging.” Researchers have made smart windows that change their optical properties to offer energy efficiency. To keep things transparent, some teams have made clear window coatings from beer waste and by layering multiple thin films made of common materials. Smalyukh and his colleagues, meanwhile, have in the past made clear gel films from wood-derived cellulose nanofibers.

Those aerogels contained randomly distributed air pockets that block heat. .IRPP_ruby , .IRPP_ruby .postImageUrl , .IRPP_ruby .centered-text-area {height: auto;position: relative;}.IRPP_ruby , .IRPP_ruby:hover , .IRPP_ruby:visited , .IRPP_ruby:active {border:0!important;}.IRPP_ruby .clearfix:after {content: "";display: table;clear: both;}.IRPP_ruby {display: block;transition: background-color 250ms;webkit-transition: background-color 250ms;width: 100%;opacity: 1;transition: opacity 250ms;webkit-transition: opacity 250ms;background-color: #eaeaea;}.IRPP_ruby:active , .IRPP_ruby:hover {opacity: 1;transition: opacity 250ms;webkit-transition: opacity 250ms;background-color: inherit;}.IRPP_ruby .postImageUrl {background-position: center;background-size: cover;float: left;margin: 0;padding: 0;width: 31.59%;position: absolute;top: 0;bottom: 0;}.IRPP_ruby .centered-text-area {float: right;width: 65.65%;padding:0;margin:0;}.IRPP_ruby .centered-text {display: table;height: 130px;left: 0;top: 0;padding:0;margin:0;padding-top: 20px;padding-bottom: 20px;}.IRPP_ruby .IRPP_ruby-content {display: table-cell;margin: 0;padding: 0 74px 0 0px;position: relative;vertical-align: middle;width: 100%;}.IRPP_ruby .ctaText {border-bottom: 0 solid #fff;color: #0099cc;font-size: 14px;font-weight: bold;letter-spacing: normal;margin: 0;padding: 0;font-family:'Arial';}.IRPP_ruby .postTitle {color: #000000;font-size: 16px;font-weight: 600;letter-spacing: normal;margin: 0;padding: 0;font-family:'Arial';}.IRPP_ruby .ctaButton {background: url(https://www.anthropocenemagazine.org/wp-content/plugins/intelly-related-posts-pro/assets/images/next-arrow.png)no-repeat;background-color: #afb4b6;background-position: center;display: inline-block;height: 100%;width: 54px;margin-left: 10px;position: absolute;bottom:0;right: 0;top: 0;}.IRPP_ruby:after {content: "";display: block;clear: both;}Recommended Reading:These windows could harness power from both outdoor sunlight and indoor artificial light Their latest material, reported in the journal Science, is a silicone-based gel with a complect microstructure.

The material, which they call Mesoporous Optically Clear Heat Insulator, or MOCHI, contains precisely arranged pockets of air that are much thinner than a human hair. The researchers make it by suspending molecules called surfactants in a liquid silicone solution. The surfactants bind to each other to form a complicated pipelike network, and the silicone sticks to the outside of these threads. Then the researchers wash away the surfactant and water, and replace it with air.

MOCHI is 90% air, and it allows more than 99% of light falling on it to pass through. Its thermal transmittance—which measures the heat is lost through a window for every degree of temperature difference between the inside and outside—beats conventional windows by a big margin.

While the best commercial windows have a transmittance of 0.2 Watts per meter square per Kelvin, the new material boasts 0.01 W/m2K. The materials used to make MOCHI are relatively low cost, but making the material in the laboratory is time-consuming. But Smalyukh believes that his team can develop more efficient manufacturing methods. Source: Amit Bhardwaj et al.

Mesoporous optically clear heat insulators for sustainable building envelopes, Science, 2025 Image: Based on a photo by Glenn J. Asakawa / CU Boulder in which Abram Fluckiger holds up a sample panel square that has five sandwiched layers of a new material nearly transparent insulation material called MOCHI.