New window insulation blocks heat, but not your view

Jeff Zehnder — Fri, 12 Dec 2025 19:31:30 +0000

New window insulation blocks heat, but not your view Jeff Zehnder Fri, 12/12/2025 - 12:31

Physicists at ��ñ�� have designed a new material for insulating windows that could improve the energy efficiency of buildings worldwide—and it works a bit like a high-tech version of Bubble Wrap.

The team’s material, called Mesoporous Optically Clear Heat Insulator, or MOCHI, comes in large slabs or thin sheets that can be applied to the inside of any window. So far, the team only makes the material in the lab, and it’s not available for consumers. But the researchers say MOCHI is long-lasting and is almost completely transparent.

That means it won’t disrupt your view, unlike many insulating materials on the market today,

“To block heat exchange, you can put a lot of insulation in your walls, but windows need to be transparent,” said Ivan Smalyukh, senior author of the study and a professor of physics at ��ñ��. “Finding insulators that are transparent is really challenging.”

He and his colleagues published their results Dec. 11 in the journal “Science.”

Eldho Abraham, left, and Taewoo Lee, right, hold up a thin sheet of MOCHI affixed to clear plastic.(Photo by Glenn J. Asakawa/��ñ��)

Shakshi Bhardwaj holds up blocks of MOCHI in different sizes. (Credit: Glenn Asakawa/��ñ��)

From left to right, Eldho Abraham, Gewei (Gary) Chen, Abram Fluckiger, Taewoo Lee, Keita Richardson, Shiva Singh, Shakshi Bhardwaj, Hanqing Zhao, Ivan Smalyukh, and Alex Adaka. (Credit: Glenn Asakawa/��ñ��)

Buildings, from single-family homes to office skyscrapers, consume about 40% of all energy generated worldwide. They also leak, losing heat to the outdoors on cold days and absorbing heat when the temperature rises.

Smalyukh and his colleagues aim to slow down that exchange.

The group’s MOCHI material is a silicone gel with a twist: The gel traps air through a network of tiny pores that are many times thinner than the width of a human hair. Those tiny air bubbles are so good at blocking heat that you can use a MOCHI sheet just 5 millimeters thick to hold a flame in the palm of your hand.

“No matter what the temperatures are outside, we want people to be able to have comfortable temperatures inside without having to waste energy,” said Smalyukh, a fellow at the Renewable and Sustainable Energy Institute (RASEI) at ��ñ��.

Bubble magic

Smalyukh said the secret to MOCHI comes down to precisely controlling those pockets of air.
The team’s new invention is similar to aerogels, a class of insulating material that is in widespread use today. (NASA uses aerogels inside its Mars rovers to keep electronics warm).

Like MOCHI, aerogels trap countless pockets of air. But those bubbles tend to be distributed randomly throughout aerogels and often reflect light rather than let it pass through. As a result, these materials often look cloudy, which is why they’re sometimes called “frozen smoke.”

In the new research, Smalyukh and his colleagues wanted to take a different approach to insulation.

To make MOCHI, the group mixes a special type of molecule known as surfactants into a liquid solution. These molecules natural clump together to form thin threads in a process not unlike how oil and vinegar separate in salad dressing. Next, molecules of silicone in the same solution begin to stick to the outside of those threads.

Through a series of steps, the researchers then replace the clumps of detergent molecules with air. That leaves silicone surrounding a network of incredibly small pipes filled with air, which Smalyukh compares to a “plumber’s nightmare.”

In all, air makes up more than 90% of the volume of the MOCHI material.

Trapping heat

Smalyukh said that heat passes through a gas in a process something like a game of pool: Heat energizes molecules and atoms in the gas, which then bang into other molecules and atoms, transferring the energy.

The bubbles in MOCHI material are so small, however, that the gases inside can’t bang into each other, effectively keeping heat from flowing through.

“The molecules don’t have a chance to collide freely with each other and exchange energy,” Smalyukh said. “Instead, they bump into the walls of the pores.”

At the same time, the MOCHI material only reflects about .2% of incoming light.

The researchers see a lot of uses for this clear-but-insulating material. Engineers could design a device that uses MOCHI to trap the heat from sunlight, converting it into cheap and sustainable energy.

“Even when it’s a somewhat cloudy day, you could still harness a lot of energy and then use it to heat your water and your building interior,” Smalyukh said.

You probably won’t see these products on the market soon. Currently, the team relies on a time-intensive process to produce MOCHI in the lab. But Smalyukh believes the manufacturing process can be streamlined. The ingredients his team uses to make MOCHI are also relatively inexpensive, which the physicist said bodes well for turning this material into a commercial product.

For now, the future for MOCHI, like the view through a window coated in this insulating material, looks bright.

Co-authors of the new study include Amit Bhardwaj, Blaise Fleury, Eldo Abraham and Taewoo Lee, postdoctoral research associates in the Department of Physics at ��ñ��. Bohdan Senyuk, Jan Bart ten Hove and Vladyslav Cherpak, former postdoctoral researchers at ��ñ��, also served as co-authors.

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McGehee and Smalyukh draw DOE funding for building energy efficiency projects

Anonymous — Thu, 02 Sep 2021 20:31:18 +0000

McGehee and Smalyukh draw DOE funding for building energy efficiency projects Anonymous (not verified) Thu, 09/02/2021 - 14:31

Jonathan Raab

Professor Michael McGehee and Professor Ivan Smalyukh are the principal investigators on two Department of Energy-funded projects to improve building technologies and energy efficiency in the built environment. Their projects are among 44 nationwide research projects selected as part of the Building Technologies Office’s competitive Building Energy Efficiency Frontiers & Innovation Technologies funding program.

The projects were selected under the program’s Topic Area 2, Advanced Building Construction category for building envelope research, development and field validation.

Professor Smalyukh is the principal investigator on a project to develop thin-film monolithic mesoporous metamaterials for ultrahigh-efficiency glazing solutions for use on windows with insulating capabilities that meet or exceed that of walls. This will allow buildings to let in natural sunlight during the day without compromising their thermal efficiency.

Professor Michael McGehee is working with his local startup, TYNT Technologies, to develop dynamic windows that feature reversible metal electrodeposition, a process that is less expensive than current manufacturing methods by a significant margin.

The Department of Energy’s investment in building energy efficiency totals nearly $83 million across 44 projects.

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