The invention of windows that could regulate the light or heat coming in, has long been in place. Many variations of these have been created, but none that could block just heat or, just the light. Blocking of heat would invariably lead to the obstruction of light partly, or completely.

But recently a team at the Cockrell School of Engineering at The University of Texas at Austin has developed a “smart window” technology that allows the passage of light while blocking heat, or vice versa.

This idea had emerged with Delia Milliron and her team when they build a smart glass coating that could block visible light, near-infrared light (NIR), or both. This had been achieved by embedding indium tin oxide (ITO) nanocrystals in glass, imbued with niobium oxide. An electrochromic material had thus been created, that was able to transmit or block light depending on the electric potential applied.

Further building of this original invention, has led to the introduction of electrochromic materials which can let one of the energy form in, while keeping the other out successfully. The cool mode permits light and blocks heat, and the heat mode does the exact opposite. These materials have proved effective screening 90% NIR and 80% visible light. Switching back and forth between modes, is a matter of seconds. There is also a bright mode that allows normal window function.

The mechanism behind this, is the use of a single, porous penetrating network that comprises of all the components. This design opens channels for both ionic and electronic change, which allows for selective blocking of heat and light. Low-cost production is currently being focused on.