If you're looking for a way to keep warm when winter winds blow, the answer may be at hand thanks to nanotechology, materials scientists say.
Researchers at Stanford University say a new nanowire treatment for fabric could lead to clothing capable of both generating heat and trapping the natural heat of our bodies more efficiently than regular clothes.
The researchers created the material by dipping ordinary cotton fabric in a solution containing silver nanowire particles, which formed a conductive network within the cloth.
By using solutions of varying concentrations, which allowed them to control the spacing of the particles in the network, they were able to find a spacing that allowed the fabric to trap 80 percent of a person's body heat, while still creating a breathable fabric that could be used in comfortable winter wear.
The conductive network can also be heated up with electricity for additional warmth when weather turns truly cold, according to their report in the journal Nano Letters.
Just 0.9 volts can warm the nanowire fabric to almost 104 degrees Fahrenheit, they say.
Almost half of all the world's energy consumption goes toward heating homes and buildings, research leader Yi Cui and his colleagues note, with considered environmental costs, especially in the production of climate-changing greenhouse gases.
While efforts have been made to reduce the energy impact of indoor heating with improved construction and insulation materials, all meant to keep more expensive fuel-generated heat within a building, Cui and his team went for an approach that focused on keeping people, not indoor spaces, warm.
Thermal nanowire fabrics could save around 1,000 kilowatt hours per person in the usual four months of winter weather, about the amount of electricity an average U.S. household consumes in a month, they estimate.
We spend a lot of money heating our indoor spaces even when no one is in them, they point out.
Just by wearing a nanowire cloth sweater around the house while outdoor temperatures fell to 50, a person could save around 300 liters of natural gas that would otherwise have been consumed in home heating, they say.
The amount of silver needed to create a nanowire garment for an individual would only cost around a dollar, Cui says, and although the nanowire fabric would require testing to be approved for use, such garments could be on the market in just a few years.