An Electricity-Free Smart Window

Nearly 30% of global energy-related carbon emissions stem from heating, cooling, and powering buildings. TBM Designs created InVert self-shading windows to reduce solar heat gain and associated energy consumption. Each window features a cavity of insulated glass containing small pieces of thermo-bimetal—a lamination of two metals, one of which expands in heat. The effect is spectacular: When the sun heats up an InVert window, the petal-shaped pieces inside it automatically flip to block light while remaining transparent, cutting cooling needs by up to 25%. Unlike other “smart” windows, InVert—which became commercially available this year—doesn’t use any energy, says TBM Designs co-founder and CEO Karen Sabath. “When the little pieces flip, they flutter like butterflies,” she says. “It gives people a sense of nature, which is what we’re ultimately trying to protect.”

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