Windows can offer beautiful natural light. But on bright days, the sunlight can bake a room. That trapped heat drives up air conditioning use and energy costs.

Now, a team of researchers at Harvard’s Wyss Institute for Biologically Inspired Engineering has designed cooler windows—by mimicking nature.

When animals get hot, tiny capillaries near the surface of the skin dilate. Circulating blood helps transfer the body heat out to the air.

In that spirit, the researchers created a super-thin silicone-rubber layer with a network of tiny sealed channels. When the rubber is stretched over a window, it’s completely transparent.

Water running through the channels absorbs heat and transfers it to the outside air. In the researchers’ model, a large window at 100 degrees Fahrenheit can be lowered to a much more manageable 86 degrees. And the energy needed to pump the water is far less than what would be needed to cool the room equivalently with air conditioning. The research is in the journal Solar Energy Materials and Solar Cells. [Benjamin D. Hatton et al., An artificial vasculature for adaptive thermal control of windows]

The team is working with architects to model energy savings if the microfluidic channels were included in an entire building’s windows. Which could warm consumers’ hearts.

—Cynthia Graber

[The above text is a transcript of this podcast.]