What are solar windows?

Solar windows pros and cons

While there are plenty of scientists, engineers and manufacturers all working to get solar windows into the hands of tomorrow’s building contractors, there are both benefits and drawbacks to consider with this new tech.

Solar windows fall into a category known as building-integrated photovoltaics (BIPV). Like solar shingles, BIPVs have a dual purpose and can help builders maximize the space and materials used for a construction project. There are two functions of a solar window: to act as a building material and to harness sunlight to generate emission-free electricity.

Solar window pros

Most buildings have windows, so solar-integrated glass has enormous potential to benefit homeowners and commercial businesses alike. With this added power generation, property owners can increase their electricity independence and reduce their long-term energy costs.

Together with a battery backup system, a set of EV chargers and other green features, solar windows are an energy-conscious construction choice that helps a property achieve sustainability recognition, like LEED (Leadership in Energy and Environmental Design) certification.

Solar window cons

As an emerging technology that hasn’t entirely made it to the commercial market yet, however, solar windows are still a bit of a mystery to many of us. For instance, what happens when a solar window stops working?

Although modern PV panels can last for 25 years or more, solar windows may not be guaranteed for the same life span. Even standard windows should be replaced every few decades to mitigate any complications from aging, so early solar window adopters run the risk of investing in a product without a proven return on investment.

When solar windows finally hit the open market, it’s likely that they’ll cost more than an average glass window installation. If the premium cost of solar windows is too high, they may not be a viable building material for construction projects with a limited budget.

How do solar windows work?

To qualify as a solar window, a building feature must generate electricity from harnessed sunlight while also functioning as a typical window. Currently, there are no commercially available solar windows, but three main technologies are being explored to help bring a product to market for residential and large-scale construction projects.

Transparent PV glass

Transparent PV glass is most likely the technology you imagine when you think about a solar window. With transparent solar cells, PV glass embeds electricity-generating technology right into its materials for a completely see-through solar panel and building feature.

Working PV glass is currently in use in a few places across the U.S. today, including on the Michigan State campus and in Boulder, Colorado. Both installations were completed using glass solar panels developed by a Silicon Valley-based company called Ubiquitous Energy.

Angled solar edges

Internationally, solar windows have also been installed at the headquarters of a Dutch bank using an entirely different technology. Unlike PV glass, these solar windows, made by PHYSEE and known as PowerWindows, do not have transparent solar cells.

Instead, PowerWindows harness, transform and transport energy from sunlight to the edges of the glass, which is framed in angled PV solar cells. While these PV cells can be seen with a close look from the building's exterior, the solar windows' surface area still appears completely transparent from the inside.

Thin-film window treatments

There are also a few ways to generate electricity by adding solar-powered technology to ordinary widows. While technically not solar windows by definition, technologies like solar blinds and solar shades can help a building capture incoming sunlight to generate electricity.

Beyond ordinary window treatments, manufacturers are also exploring ways to apply thin-film or transparent solar cells directly to the glass surface of a window, such as with PV plastic sheeting.

The future of solar windows

With PV roof tiles, solar trees and even solar paint, you can “solarize” almost anything in the 2020s. “Solar windows will be pretty common any day now. As far as building integrated PV goes, solar glass is huge, as well as solar shingles and siding,” Hayden Kleinhans, manager of land development at Invenergy, a multinational sustainable energy company, told us.

While it’s tough to pinpoint an exact timeline, the future of solar windows may be nearer than most people think. In particular, Ubiquitous Energy expects to have its first U.S. manufacturing line in operation by 2024. As we gaze into the future of sustainable construction, solar windows have the potential to play a strong role in new building projects of all shapes and sizes.

Bottom line

Although solar windows aren’t commercially available today, the technology has been in development for many years and may be hitting the market sometime soon. As home and commercial construction teams look for more ways to create sustainable structures, solar windows are poised to have a large impact on the green building industry in the 2020s.

In the meantime, traditional PV solar panels remain a great way to help drive down a property’s long-term electricity costs and carbon footprint. While waiting for the next big thing in PV technology to develop, you can start your green energy journey any time with one of today’s best solar energy companies.