The US Inflation Reduction Act passed in August contains tax and investment incentives for a number of clean-energy technologies, including electric cars, solar panels and wind turbines. But the 750-page document also features a 30% tax credit for a lesser-known player in the push for energy efficiency: dynamic glass.
Dynamic glass, also referred to as smart glass, has essentially the same effect as “Transition” sunglass lenses: It darkens when exposed to sunlight. Except in this case the tinting effect is created by an electrical charge, which can be activated naturally or by remote control. For modern buildings that feature a lot of glass, the technology can be used to temper intense sunlight and expand the use of shared spaces. But as high energy costs force conversations about efficiency, schools, stores, airports and other public buildings are also looking to dynamic glass as one small-scale energy-saving solution.
“The addition of dynamic glass to the [IRA] is a watershed moment,” says Jordan Doria, the global marketing director for Minnesota-based SageGlass, one of the largest manufacturers of dynamic glass in the world. “It opened up the market in new ways.”
In Northern Chicago, the 70,000-square-foot Sunset Ridge School features 1,223 rooftop solar panels, rain gardens, a living wall and a library with smart glass made by Mississippi-based View Inc. There’s no glare, no sudden shifts in temperature and no need to move every 20 minutes to avoid direct sunlight. “It’s allowing us to have more consistency in that instructional space,” says Ivy Sukenik, assistant superintendent and principal of the school.
Aaron Otten, chief executive of Elkhorn Valley Bank in Nebraska, also swears by the smart glass in his office building, construction of which was completed last summer. “I love the glass,” he says. “You always have some level of natural light and I think in general you’re in a little bit of a better mood.”
In 2018, German supermarket chain Lidl started installing smart glass at 200 of its stores, resulting in what William Harwood, communications director for Lidl US, says was “observable aesthetic benefits for our customers and team.” Harwood says the company has since saved significant amounts of energy during peak temperatures, and uses less air conditioning. Lidl plans to install dynamic glass in its UK and Spain locations as well.
When smart glass was first marketed in the mid-2010s, SageGlass’s Doria says energy savings weren’t enough to sell the product; companies found more success pitching dynamic glass as a “lifestyle” improvement. At one conference in 2014, for example, View Inc. Chief Executive Officer Rao Malpuri said dynamic glass could save 20% in HVAC energy consumption, then immediately followed it up with the “far bigger” benefit: “If you can create a space with more natural light, studies have shown that people recover faster, students are able to learn in a better learning environment [and] employees are much more productive.”
But another adoption barrier — cost — continues to be a challenge. Making and installing smart glass is still overly expensive, says Ulrich Knaack, chair of facade structures at Darmstadt Technical University. Prices vary widely based on location, design, orientation and size, but one 2018 study by Project Drawdown, a nonprofit organization focused on carbon-reduction solutions, found dynamic glass to be at least three times more expensive than conventional glass (though installation costs are similar). While increased production will eventually make smart glass cheaper, Knaack says that price parity isn’t coming anytime soon.
Further complicating the smart glass sales pitch is the difficulty of pinpointing exact energy savings. Studies suggest it’s around 10% to 20%, but getting more specific is difficult: Many installations are in new buildings, and different companies use different methods and materials to tint the glass, making an industry standard hard to identify. SageGlass and View, for example, use electrochromic glass: Coatings on the interior of the glass are filled with small batteries that can be charged by an electric current; when the current is applied, either by remote control or by heat from the sun, the batteries move from one layer to another and create a tinting effect. Eyrise, however, uses liquid crystal glazing. In that method, when a low electric current is applied to the liquid crystals, they align to let light through. When there is no charge, the crystals scatter randomly and the windows become opaque.
Anecdotal evidence also suggests decent energy savings. The Brownsville/South Padre Island International Airport in Cameron County, Texas, was built with dynamic glass made by SageGlass. In July, the airport turned off its smart glass for one week and compared energy use to the same week in July 2021, finding 27% less energy use. “Employees needed to use personal fans to stay cool,” the airport and SageGlass noted in a joint study.
Eyrise also estimates utility savings from its smart glass at 10% to 20%, according to Filip Roscam, the company’s head of marketing communication and experience design. He says Eyrise has seen success in the Nordics and Switzerland, where buildings are well insulated “so the risk of overheating is very high.”
Project Drawdown, for its part, estimates the potential energy savings from dynamic glass at 9%, factoring in cooling and lighting. Although its study concedes that smart glass reduces energy use and operating expenses, Project Drawdown also concludes that it would be difficult to justify the cost for any building that doesn’t also need other upgrades.
Those “other upgrades” may be key to smart glass’s next act. The technology’s proponents have thus far leaned on aesthetics, but a global energy crunch and the impacts of climate change are moving the conversation toward efficiency, especially within companies. “We’re seeing the shift as there is more talk about climate-adaptive design,” says Doria at SageGlass. “We weren’t hearing this three years ago.”
Roscam at Eyrise agrees. “Customers are using our products to increase their green certifications,” he says. “You can power an entire building of dynamic glass windows with one solar panel.”
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