What Are Solar Windows?

How do solar windows work?

Solar windows generate electricity from harnessed sunlight while functioning as a typical window.

1. Sunlight is captured. Solar windows use special materials that can absorb sunlight like regular solar panels, but they're designed to let most light pass through so you can still see outside.
2. Light is converted into electricity. The absorbed sunlight gets converted into electrical energy through photovoltaic cells (the same technology used in rooftop solar panels).
3. Power is collected. The electricity is gathered and sent to the building's electrical system or stored in batteries.

Types of solar window technology

Three main technologies are being explored to help bring a product to market for residential and large-scale construction projects: transparent PV glass, angled solar edge and thin-film window treatments.

Transparent PV glass

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

Solar windows convert energy from the sun into electricity, like solar panels.

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

The edge approach uses a clear window that funnels energy to solar cells around the frame. 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 glass edges, framed in angled PV solar cells. While these PV cells can be seen from the building's exterior, the solar windows’ surface area still appears completely transparent from the inside.

Thin-film window treatments

Solar films or treatments can be applied to existing windows. 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.

Did you know?

Solar windows fall into a category known as building-integrated photovoltaics. 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.

» MORE: Solar panels vs. solar shingles

How much do solar windows cost?

Just the glass components of solar windows typically start around $5 to $26 per square foot. After you include installation, wiring and other expenses, the total jumps to approximately $50 to $86 per square foot.

This makes solar windows considerably more expensive upfront compared to the cost of solar panels.

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.

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 window advantages

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

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

Solar window disadvantages

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

Unlike rooftop panels that can be individually replaced, a broken solar window might require replacing an entire building feature. Will homeowners need specialized technicians? Can damaged solar windows be repaired, or must they be completely replaced? These practical questions remain largely unanswered.

» MORE: Solar energy pros and cons

How efficient are solar windows at generating electricity?

Solar windows, also called transparent or semitransparent photovoltaics, are still emerging, and their efficiency is lower than traditional solar panels. Most early-stage prototypes generate about 1% to 5% efficiency, meaning they convert a small portion of incoming sunlight into electricity. Newer, commercially oriented designs are improving, with some reaching 10% to 15% efficiency under ideal conditions.

By comparison, standard rooftop solar panels typically achieve 15% to 22% efficiency, depending on the technology and manufacturer. This gap exists because solar windows must balance energy production with transparency, allowing visible light to pass through while still capturing energy from other parts of the solar spectrum.

Key efficiency benchmarks

• Prototypes: Roughly 1% to 5% efficiency
• Emerging commercial products: Roughly 10% to 15% efficiency
• Traditional rooftop solar panels: Roughly 15% to 22% efficiency

One key metric for evaluating solar windows is visible light transmission (VLT). VLT measures how much natural light passes through the glass. Higher VLT means clearer windows and better daylighting, but usually lower energy output. Lower VLT can improve power generation but may darken interiors, similar to tinted glass.

Performance factors

• Materials: Organic photovoltaics and thin-film coatings impact efficiency
• Spectral selectivity: Systems absorb UV/IR light while letting visible light pass through
• Orientation: South-facing windows typically generate more electricity
• Sun exposure: Shading, climate and window size all influence output

In practice, solar windows are best viewed as a supplemental energy source rather than a full replacement for rooftop solar, especially in residential settings where maximizing energy output is the primary goal.

Solar window alternatives

If you’re thinking about getting solar windows, you should also consider solar panels and solar screens.

Solar windows vs. solar panels

Solar windows generate much less electricity than rooftop solar panels because they must balance transparency with power generation. The more transparent a solar window is, the less sunlight it can capture for electricity. Current prototypes typically convert only 1% to 5% of sunlight into electricity, compared to 15% to 22% for standard rooftop panels.

Traditional PV solar panels remain a great way to help drive down a property’s long-term electricity costs and carbon footprint. Modern PV panels can last for 25 years or more, but solar windows may not be guaranteed for the same life span.

Solar windows vs. solar screens

Solar windows are special glass panels that generate electricity from sunlight using built-in photovoltaic technology, while still letting in natural light. They can help lower energy bills by producing renewable power and providing some heat and glare reduction, but they’re more expensive and usually installed during new construction or major renovations.

Solar screens, on the other hand, are mesh coverings that fit over existing windows to block heat, glare and UV rays. They don’t make electricity, but they’re much cheaper, easy to install and can significantly reduce cooling costs in hot weather. Essentially, solar windows create power, while solar screens simply keep heat out.

Solar windows vs. solar screens vs. solar panels

FAQ

Bottom line: 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.

It’s tough to pinpoint an exact timeline, but the future of solar windows may be nearer than most people think. 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.

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.