Every single second, the sun blasts the Earth with more energy than humanity could ever use in an entire year. The challenge has always been figuring out how to capture it efficiently, and how to make that energy useful. Two centuries of scientific progress later, we’ve arrived at today’s sleek and efficient solar panels.
But today, not all solar panels are built the same. You’ve probably heard of bifacial solar panels — those shiny, double-sided units that everyone seems to be talking about. But what is a bifacial solar panel, and are they actually better than traditional mono-sided solar panels?
To answer these questions, we’re going to provide a bit of background, break down the main types of solar panels, and explain what it all means in practical terms for your own solar panel setup. Don’t worry, you won’t need a physics degree for this. Let’s jump in!
To kick things off, we’re going to quickly explain the history of solar, and where bifacial panels come from. If you’re not interested in that and just want to know what bifacial panels are and whether or not you should buy them, skip to the next section. If you’re interested, let’s get started.
The story of solar energy stretches back a lot farther than today’s sleek rooftop panels. As early as the 7th century B.C., humans used magnifying tools and mirrors to concentrate sunlight for lighting fires, and evidence they did so can be found in modern-day Greece and China.
Later, passive solar design, like south-facing windows and using building materials that absorbed heat from sunlight, became common in Roman bathhouses and other ancient structures.
In the 19th century, scientists began to unlock the mechanisms behind sunlight and electricity. In 1839, French physicist Alexandre Edmond Becquerel observed the photovoltaic effect, showing that certain materials generate electric current when exposed to light.
In the 1870s, selenium-based cells were created and had some limited use, but they had efficiency ratings under 1% (aka they were a waste of time). The real breakthrough came in 1954 when scientists at Bell Labs (Daryl Chapin, Calvin Fuller and Gerald Pearson) created the first practical silicon photovoltaic cell.
This was a key turning point for solar power as we know it. After that, solar cells started to be used for space exploration. In 1958, the Vanguard I satellite was partially powered with basic solar cells, proving the technology could even work in orbit.
During the 1970s, the OPEC oil crisis pushed western governments, including those of the United States, Canada, Australia and most of Europe, to invest heavily in solar research. The aim here was to find alternatives to the middle eastern oil their countries had become reliant on.
All of this research helped drive down solar panel costs and improve manufacturing techniques. For example, in 1978, the United States passed the Solar Photovoltaic Energy Research and Development Act, which was designed to accelerate the development of new solar technology.
In the years that followed, solar PV tech moved from niche applications (like satellites) to more mainstream uses. By the early 2000s, residential solar panel systems became a common sight on rooftops across North America and Europe.
Today, solar power is growing faster than any other energy technology. Improvements in panel efficiency have led to lower costs per watt, and the spread of off-grid, grid-connected, and hybrid solar power systems.
Now that you have a bit of a background on how solar panels came to be, let’s look at the three main types (we’ll discuss bifacial panels and how they differ below this section):
Monocrystalline solar panel cells are made from a single pure silicon crystal. This is what makes these panels sleek, efficient, and durable, with most topping out at 20% efficiency.
They usually perform better in low light and last longer than other types of panels, but they also cost more to make. That’s why you’ll usually see them on rooftops or in smaller systems where space is at a premium, but people are willing to pay extra to use that space to its full potential.
These 460W Aptos Monofacial Panels are a good example of what they look like.
The solar cells in polycrystalline solar panels are made by melting fragments of silicon together. They’re cheaper to make and purchase, but slightly less efficient (usually around 15–17%). They also have a distinctive blue color with a speckled look.
While they’re noticeably less efficient than monocrystalline panels, they’re extremely common in residential and commercial systems thanks to their lower cost per watt.
The solar cells in these types of panels ditch the silicon wafers altogether and use ultra-thin layers of materials like cadmium telluride or amorphous silicon instead. They’re light, flexible, and can even be integrated into building materials like windows and roofing. The trade-off? A low efficiency, usually about 10–12%, and a shorter lifespan.
These 200W BougeRV Flexible Solar Panels are a good example of a basic thin-film panel.
That brings us to the star of the show—bifacial panels.
Traditional solar panels (called monofacial panels) only collect light from one side: the front, which is the part that faces the sun. On the other hand, bifacial solar panels collect light from both sides of the panel.
These solar cells are protected with transparent materials (almost always high-strength glass) on both the front and the back. This allows them to absorb not just direct sunlight, but also light reflected from the ground, nearby buildings, or even snow behind the panel itself.
That means the back side of the panel contributes to generating real solar electricity, especially if it’s mounted over bright or reflective surfaces. Depending on the setup, bifacial panels can generate 10–30% more electricity than traditional panels.
Typically, a bifacial solar panel will be made using monocrystalline solar cells, so they’re not only more efficient because they’re capturing sunlight on both sides of the panel, they also have more efficient photovoltaic cells.
Take these Sirius PV 415W Bifacial Solar Panels as an example. They contain monocrystalline solar cells, but have a bifacial design, enabling them to have a high wattage and very impressive efficiency. They’re actually the same panels we use here at The Solar Lab (and the panels we usually recommend).
Inside a bifacial panel, the solar cells themselves are designed differently. Instead of a solid aluminum back contact (like in monofacial panels), bifacial panels have a transparent or grid-like contact layer.
Light passes through the silicon wafer and gets absorbed from both sides. Each photon that hits the panel, either the front or the back, can knock an electron loose and create the electrical current that is captured in the form of solar power.
To protect both sides, bifacial panels use glass-on-glass construction instead of the traditional glass-and-plastic sandwich design. A common misconception is that bifacial solar panels are just two monofacial panels that are glued together, but that’s wrong. Bifacial solar panels use a single, purpose-built design that is optimized for light capture in both directions. They’re one solid solar panel that just has a more efficient design.
As mentioned above, we’ve been running a large array of bifacial Sirius 415W Panels on a massive Chiko GroundFlex Solar Panel Mount. We use this combination for running all of our inverter and battery tests, as well as just powering our home and garage.
The results? Excellent.
These bifacial panels deliver noticeably more power than other panels we've tested, especially during winter when sunlight reflects off snow. The back-side generation helps offset darker months in the colder climate where we’re located, and that’s a huge advantage when daylight hours are reduced.
We’ve also tested their durability (yes, including full-speed pitching an apple at one). They survived without so much as a scuff. So, not only are bifacial panels more effective at generating power, they are built tough.
Put simply, you get more power from a panel with the same dimensions as a less efficient monofacial panel, while the double-glass design means they’re less likely to warp or degrade over time.
To keep things simple, here’s a quick rundown of the advantages and disadvantages of bifacial solar panels:
You can clearly see above that the pros outnumber the cons when you're talking about bifacial solar panels, but there is still an element of personal preference (and budget) when you're deciding if they're worth paying extra for.
If your setup allows reflected light to reach the backside of your panels, whether from white roofing, gravel, wet grass, or snow, then absolutely, bifacial panels would be worth the investment.
For people chasing energy independence or looking for a future-proof solar panel array, bifacial panels are one of the smartest upgrades you can make. They produce more power, last longer, and handle harsh environments better than most standard panels.
Personally, we’re all-in on them. They’ve proven their worth powering our studio and tests, and we’ve yet to find a reason to go back to cheaper panels. If you’re also serious about going solar and saving money, they’re a bit of a no-brainer. Still, asssess your own needs and budget before ordering panels.
From the first photovoltaic experiments in the 1800s to powering satellites and now entire neighborhoods, solar technology has come a long way. Solar panel design has also changed quite a bit in that time, and given that they’re tougher and more efficient than the alternatives, bifacial panels feel like the next step forward.
And at the end of the day, going solar is all about: energy independence. Whether that means slashing your electricity bills, living completely off-grid, or just having the confidence that you won’t be left in the dark during the next blackout, you’ll want to generate power as efficiently as possible. So, our recommendation would be to choose bifacial solar panels for pretty much any type of solar setup.
If you’re interested in learning more about solar panels, we also have a guide that explains folding panels, and covers why we usually recommend rigid panels instead: Folding Solar Panels vs Rigid Solar Panels.
Sirius 415W Bifacial Solar Panels: wwwSignatureSolar.com
Use Code: SOLARLABGET50 for $50 Off Your Order
Signature Solar Panel Collection: www.SignatureSolar.com
Use Code: SOLARLABGET50 for $50 Off Your Order
Shop Solar Panel Collection: www.ShopSolar.com
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