PolyU smart window film cuts building energy use and carbon emissions by regulating light and humidity

Researchers at Hong Kong Polytechnic University have developed a smart window film that automatically adjusts light and humidity to reduce building energy consumption. The film uses a dual layer of nanofiber and hydrogel to lower indoor temperatures by up to 21.1 degrees Celsius during the day and cut humidity from over 91% to around 54% at night. The team estimates the film can reduce annual energy use by more than 20% and cut carbon emissions by over 18 kilograms per square meter each year. Unlike thermochromic or photochromic smart windows, this film uses low cost, eco friendly materials and resists bacteria and dust. The payback period is only one to two months based on manufacturing costs. The film is especially suited for humid tropical and subtropical regions like Hong Kong, where air conditioning demand is high. The research was published in Advanced Energy Materials.