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Disruption Alert: Transparent Solar

A conversation with Ubiquitous Energy about the opportunity for renewable energy and how solar windows can enable smarter homes

Aesthetics have long been a limitation to traditional solar’s application, largely relegating the dark-colored, large panels to rooftops. Ubiquitous Energy is seeking to disrupt the solar market by pioneering a transparent photovoltaic glass coating that captures the sun’s invisible rays and convert them to power, thereby allowing all visible light to still pass through a window.  

Ubiquitous Energy CEO Susan Stone explains the company developed a low-emissivity coating that can be applied to any window and fit into the existing supply chain. For example, a window manufacturer will purchase its IGUs, which will be manufactured to the correct size and with the transparent solar coating already applied. Then, the IGU would ship to the window manufacturer, who would frame the window before installing it in a home. There are just a couple pigtail wires coming off the corner of the IGUs that harvest the electricity, she says.  

Stone notes how the company sees it as “critical” to ensure the window is installed the same way as any other window and doesn’t disrupt the trades. “Everybody gets to do everything the same way they’ve always done; we’re just another piece of the chain,” she says.  

Window + Door sat down with Stone and Veeral Hardev, vice president of strategy, to discuss the opportunities for solar and progression toward introducing more sustainable, renewable energy sources into the country’s building stock. Following is an excerpt from the conversation:

WD: Why is now the time to bring solar energy into homes?

Stone: We’re at this really pivotal moment for climate tech overall, but especially for increasing the efficiency of our homes and buildings. It’s on the minds of virtually everyone today, from individual homeowners to tenants in commercial buildings. There’s been a dramatic shift in focusing on building with more efficient materials, making our homes smarter and working for us, and decarbonizing our commercial portfolios.

Hardev: We’ve long wanted more energy technologies where we can. One challenge to date is how to get solar energy into buildings, which has really just been traditional solar on the rooftop. You can’t make windows out of it. Regarding cost, the solar panels themselves and materials are pretty inexpensive. Eighty to 90 percent of the actual cost is in the labor, installation and infrastructure you need for a rooftop system.

I bring this up because we have a technology you can apply to surfaces like windows; we don’t have fixed costs like labor and infrastructure. This is a coating that’s going right on the glazing that’s getting manufactured and processed almost the exact same way that low-e glass and windows are made today. There will be costs of our materials and putting it together, but it won’t be something so significant that it won’t be economical.

The environment is also changing. Investors have come in on this recent financing round, whereas a couple of years ago people were talking about investing in technologies like this but not taking action. Now we’re seeing a lot more interest in people taking action.

WD: Where do you see this technology gaining ground?

Hardev: We’re starting with windows, which is where think the biggest potential impact from this technology is. Windows are divided in two major market segments: residential and commercial. On the residential side, there are a couple things you can do. One is to use these windows as traditional solar panels.

But what we think is really compelling and we’re getting enthusiasm around is using this technology to make smart windows where you can integrate advanced features right into the glazing, such as sensors, automation for venting, driving automatic window covering shades, motion detection and security features. It’s not just the Rings, Nests and doorbells anymore for smart homes. Every part of the home will be interconnected. We see windows as one piece of the envelope that hasn’t yet joined that wave.

WD: Tell us more about the trend toward smart homes and how windows can be a part of that.

Stone: I love the smart window application. We provide the power platform. The glass is making the electricity, which is stored in a small battery that is tucked away. You install it like a traditional window—there’s no disruption to the trade—but it enables functionality. Our windows have been apertures to the world since they were invented. There are so many features that should be at our windows that belong there. This opens up a whole new world for what a window can do for us.

We talk a lot about how much they are of the building envelope. Our newest investor, Andersen Corp., told us they’re seeing people wanting to build with more glass as a big homeowner trend. Making windows active is a big part of the opportunity to allow people to build with more glass and keep the efficiency of their home.

Hardev: We’re not making tradeoffs. The window still performs as a highly energy-efficient window and as a low-e window. Aesthetically, there’s no obstruction or color. We spent a lot of time on our research and development to ensure we can keep those same aesthetic qualities while providing renewable energy generation via a functioning solar device.

WD: How efficient is the solar and what can that efficiency enable?

Hardev: We’re at efficiencies of three to five percent. We took a look at how much power is needed to enable smart window functions and concluded that even with just a few percent of power conversion efficiency we could enable all of those things. Traditional solar is in the order of 15 to 20 percent efficiency. The goal isn’t for us to compete with traditional and get to that high energy efficiency or power production. We see this technology as being complementary. It could work in combination to create a better system overall and reduce reliance on fossil fuels.

We have a pretty long pipeline in terms of our R&D where performance will be much higher. We’ve publicly reported efficiencies close to 10 percent. That’s where it starts to get really exciting for things like skyscrapers that have 100 percent curtain wall or glazed area. Oftentimes those kinds of buildings are already putting in curtain wall glazing and we’re piggybacking off of that.

If you have windows that are like solar panels, you can see how this could be distributed on a broad scale. Each home, building and structure could have its own energy generation windows. To prevent rollouts and blackouts, we think this is part of the wave of the future of how energy will be distributed and making it overall more reliant. We’re changing the way we get and use our energy and solar is a big part of this.

Stone: We occasionally get people saying we’ll never be as efficient as conventional solar because we’re not harvesting the visible light so by definition limiting our production, which is absolutely true. What gets me so excited is we unlock an opportunity to create electricity from surfaces that have never been able to generate electricity before. There’s a real opportunity to be share with the grid and be a component of a truly distributed system through what you’re going to install anyway—a window. Why not make them solar assets in addition to all the other benefits they provide us.

WD: What could encourage more sustainable technology on the legislation and code landscape?

Stone: Tax incentives that provide incentives for residential and commercial building with solar technology are incredibly valuable to us and other companies that are bringing new technologies online. That’s in part because we’re raising capital to fund our factory, which needs to be able to make floor-to-ceiling glass, not just these prototypes. Incentives help supercharge early demand. We’re committed to mass adoption, which is why we made decisions to fit right into the supply chain. That’s about mass adoption, keeping costs down and empowering the channel to make this technology widespread.

Hardev: On the code side we’re seeing things happening that are going to require technologies like ours to be used. For example, Title 24 in California and Local Law 97 in New York City drive a lot of these kind of aggressive changes to the code. They’re getting to a point now where the code is going to start requiring advanced glazing solutions that are really expensive. We see an opportunity for other technologies likes ours to start getting written into that code, which will help drive adoption. It’s when you see technologies getting more mature and built into building code when you see broad-scale adoption.  


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Laurie Cowin

Laurie Cowin is editor of Window + Door. Contact her at