Researchers at the Lawrence Berkeley National Lab designed a way to dynamically control light and heat transfer through windows, which can save heating/cooling and lighting costs by reducing the amount of energy needed to perform those functions.

The technology works by embedding nanocrystals – invisible to the naked eye – within the glass that can modify light transferred through the window. “Independent control over NIR [near-infrared] light means that occupants can have natural lighting indoors without unwanted thermal gain, reducing the need for both air-conditioning and artificial lighting. The same window can also be switched to a dark mode, blocking both light and heat, or to a bright, fully transparent mode,” according to a statement on the lab’s website.

Energy lost through windows represents 4% to 5% of total annual US energy consumption, at a cost of $50 billion, lab scientist Howdy Goudey said in a video about the research (included below). The technology is featured in a paper published in the current issue of the journal Nature and has already won an R&D award. The researchers are reportedly “in the early stages of commercializing their technology,” and if the windows can be economically mass produced, there would likely be strong demand from the burgeoning energy efficient product market.