Big building companies are backing smart-glass start-ups Soladigm and Sage Electrochromics to get auto-tinting glass out of the labs and into buildings.
This photo from Sage's headquarters in Minnesota shows how each row of windows can be tinted with a switch or a schedule.
(Credit: Sage Electrochromics)
Windows that shade automatically have been part of high-tech home demos for years, but there are signs that smart glass is leaving research labs and heading into actual buildings.
Building-materials maker Saint Gobain acquired Sage Electrochromics last week, and another smart-glass start-up, Soladigm, signed a distribution deal with Guardian Industries, one of the largest glass manufacturers.
Scientists have toiled for years on developing glass that can automatically tint based on the amount of light coming in, but technical challenges have meant that the technology is hardly used.
The investment by large companies in auto-tinting window glass signals that the technology is mature and affordable enough, at least for commercial customers. "We have been carefully evaluating the landscape for the right technology that is ready for scale and widespread adoption," Scott Thomsen, Guardian Glass Group president, said in a statement.
Auto-tinting glass cuts glare and reduces energy use by blocking out heat from sunlight but letting in sunlight, to reduce the need for artificial lighting. Particularly for buildings with large, glass enclosures, it's an attractive alternative to mechanical blinds, according to Sage Electrochromics.
Sage makes a nano-engineered coating that darkens when it's electrically activated, so it can be tied into a building-management system to tint on a schedule or be operated with a switch.
Soladigm licensed a material from Lawrence Berkeley National Laboratory that tints when an electric charge is applied. Its Dynamic glass relies on sensors to detect light and temperature and adjust tint.
These electrochromic coatings and wiring add cost, but give architects the flexibility to use glass, and can cut energy costs substantially. Soladigm estimates that auto-tinting can save 25 per cent on heating and cooling, and reduce peak-time heating by 30 per cent.
Soladigm is building a factory in Mississippi, and Sage Electrochromics has one in Minnesota, with a second one in Minnesota expected to start delivering products early next year, according to a representative.
Auto-tinting for regular household windows is likely years away, but proving the technology in skyscrapers and office buildings is a step towards consumer smart windows.