The Innovative New Window Insulation That Could Forever Change Energy Efficiency

In the past couple of decades, there's been a revolution in sustainable construction materials, with innovators focusing on features like carbon neutrality and sustainability. From engineered bamboo to transparent window films, some of the top building materials are focused on energy efficiency. This week, a team of physicists at the University of Colorado Boulder announced a new window insulating material: Mesoporous Optically Clear Heat Insulator, or MOCHI for short. No, MOCHI is not a dessert — it's a transparent material that traps heat, and this is one invention that could change the future of energy efficiency.

Since Mesoporous Optically Clear Heat Insulator is quite a mouthful, let's break it down to decipher what it actually means and what it does. On the nanoscale, mesoporous simply means "middle-sized openings," and it refers to a network of pores in a material. These pores increase the surface area and make it possible for the material to trap air and gases. Because air has such a low thermal conductivity, almost all insulators are basically just air holders. In recent years, material scientists have been working with mesoporous materials to trap air better; the aerogels that NASA has been using to insulate electronics in the Mars rovers are an example.

However, as Ivan Smalyukh, the senior author of the study, says, "Finding insulators that are transparent is really challenging." MOCHI traps heat like a traditional insulator while staying clear enough to see through, keeping your house warm and cozy while allowing you to enjoy the view.

According to the Department of Energy, windows account for about 30% of a home's heat loss, so finding a transparent solution would help reduce home energy costs, which is significant considering that buildings account for about 40% of worldwide energy consumption. This innovation is based on the same kind of bubble wrap technology that made NASA's aerogels possible, but the pores in aerogels are distributed randomly, resulting in a cloudy or smoky appearance. With MOCHI, transparency was the goal, and it was achieved by using a special solution of molecules that were then replaced by air. In the final product, air comprises about 90% of the total volume of this new mesoporous material.

To understand further how the UC Boulder teams' new MOCHI material works, imagine how heat is transferred from one molecule to the next when they bump into each other. The more the molecules bump into each other, the warmer they get, and the faster they go. With a mesoporous material, the walls of the pores prevent molecules from bumping into each other, which stops the transfer of heat. "The molecules don't have a chance to collide freely with each other and exchange energy," Smalyukh said.

Potentially, MOCHI materials are more than just insulators. Since this material traps heat, the opportunities are endless if it could be harnessed. As Smalyukh notes, "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."