University of California, Los Angeles (UCLA)

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 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. Window performance can be improved either by transparent, adhesive products that can be applied directly onto existing windows or by manufactured windowpanes that can be installed without replacing the window sash that holds the windowpane in place. Innovative technologies to enable inexpensive, high-performing products in these two categories are needed to accelerate effective retrofit options.

The University of California, Los Angeles (UCLA) will harness advances in nanotechnology to produce thermally insulating transparent barrier (THINNER) coatings to reduce heat losses through single panes of glass. The porous coatings consist of multiple layers of silica/titania films that can simultaneously control the transmission of heat, light and thermal radiation. The internal structure of the coatings is determined by a polymer lattice that is later removed. This leaves a robust porous oxide layer that is transparent and thermally insulating. In addition to reducing heat loss, the coatings will reduce water condensation on the inner window surface and block harmful ultraviolet light. The project will also develop a scalable, high-temperature spray-on process to inexpensively deposit the coating onto glass at the factory.

If successful, UCLA’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.