The future of winter clothes has arrived, and it’s even better than wrapping yourself in an electric blanket until spring. Researchers have created a new cloth that warms up with just a bit of electricity and traps body heat more efficiently than standard cotton fabric. The scientists dipped ordinary cotton cloth in a solution of silver nanowire particles, which form a conductive network embedded in the cloth. By varying the concentration of the solution, the researchers were able to control the particles’ spacing in the network, ultimately finding the sweet spot where the fabric trapped close to 80% of the heat our bodies radiate while still allowing water molecules to pass through, they will report this month in Nano Letters. That retains the breathability of the material, making it possible to create comfortable winter clothes out of the new fabric. For extra-cold days, electricity can provide an additional boost: The cloth warms up to nearly 40°C when powered with a mere 0.9 volts of electricity. Wearing such toasty clothes could help reduce the energy we spend on wasteful residential heating, the researchers say. They estimate that a person requiring indoor heat during a period of 4 months with average outdoor temperatures at about 10°C could save 1000 kilowatt hours of energy per year, or roughly 300 liters of gas, just by wearing a nanocloth sweater at home.