Numerous U.S. buildings have single-pane windows that do not insulate the building or its occupants as well as double-pane units or other advanced windows. Single-pane windows are also inferior in condensation resistance and occupant comfort. However, complete replacement of single-pane windows with efficient, modern windows is not always desirable or feasible due to cost, changes in appearance, and other concerns. Retrofitting, rather than replacing, single-pane windows can reduce heat loss and save roughly the amount of electricity needed to power 32 million U.S. homes each year. Transparent adhesive products that can be applied directly onto existing windows could improve window energy efficiency and other important qualities without substantially affecting the window’s appearance.
Project Innovation + Advantages:
Oak Ridge National Laboratory (ORNL) and its partners are creating a highly transparent, multilayer window film that can be applied onto single-pane windows to improve thermal insulation, soundproofing, and condensation resistance. The ORNL film combines four layers. Low-cost, nanoporous silica will be used to improve thermal insulation. A layer of a sound-absorbing polymer, which is commonly applied to windows for soundproofing, will be added between the silica sheets to reduce outside noise infiltration. A final outside superhydrophobic coating layer will minimize the condensation. A low-emissivity film will be added to minimize heat transfer out from the conditioned interior.
If successful, ORNL’s innovations will enable energy-efficient retrofits for the substantial remaining stock of single-pane windows in the United States. Retrofitting single-pane windows could produce significant economic and environmental benefits. These technologies could help reduce building energy consumption and save money for homeowners and businesses. Consumers adopting these retrofits could also benefit from improved window performance, including greater comfort and condensation resistance in cold weather and better soundproofing. Finally, by consuming less electricity, natural gas, and/or heating oil to warm a building, these technologies reduce the greenhouse gas emissions associated with using these energy sources.