Bifacial Solar Panels Explained: How They Work and If They’re Worth It

The solar industry is in a constant state of innovation, with engineers relentlessly pushing the boundaries of efficiency. For the past several years, the most significant commercial innovation has been the rise of bifacial solar panels. Unlike their traditional monofacial (one-sided) counterparts, bifacial panels are designed to capture sunlight from both sides, promising a significant boost in energy production. This technology is no longer a niche concept; it’s rapidly becoming a new standard, especially in commercial and utility-scale projects.

But does this powerful technology make sense for a typical homeowner? Is the extra cost of bifacial solar panels justified by the performance gains on a residential roof? The answer is nuanced and 100% dependent on how and where they are installed. A bifacial panel installed incorrectly will perform no better than a standard panel, wasting its key advantage.

This comprehensive guide will explain the technology, break down the critical factors that determine its performance, and provide a transparent, data-driven answer to the question: “Are bifacial solar panels worth it for your home?”

What Are Bifacial Solar Panels?

A bifacial solar panel is a photovoltaic (PV) module designed to generate electricity from both its front and rear faces. While a traditional monofacial panel has an opaque, solid backsheet, a bifacial panel uses either a transparent (clear) backsheet or, more commonly, a second pane of glass, creating a “dual-glass” module. This design allows the solar cells inside to capture sunlight that hits the front of the panel directly, as well as sunlight that reflects off the ground (or roof) and hits the back of the panel.

How do bifacial panels work differently from monofacial panels?

The core difference lies in capturing reflected and scattered light.

• A monofacial panel only absorbs direct sunlight (irradiance) that strikes its front side. Any light that passes between the cells or reflects off the backsheet is lost as heat.
• A bifacial panel absorbs direct irradiance on the front, just like a monofacial panel. Crucially, it also absorbs reflected light (known as albedo) that bounces off the surface beneath the panel and strikes its rear side.

Think of a monofacial panel as a standard mirror, only reflecting light from one side. A bifacial panel is like a translucent, two-way mirror, capturing light from both directions.

What is “bifacial gain”?

Bifacial gain is the “extra” electricity generated by the rear side of the panel, expressed as a percentage of the front side’s generation. If a panel produces 100 Watts from its front side and 10 Watts from its rear side, it has a bifacial gain of 10%. This gain is not a fixed number; it is highly dynamic and depends entirely on the installation environment. Manufacturers often claim a potential gain of “up to 30%,” but achieving this requires perfect, laboratory-like conditions.

What technology do bifacial panels use?

Bifacial technology pairs perfectly with modern, high-efficiency cell structures like N-Type TOPCon and HJT (Heterojunction). This is because these N-Type cell architectures (as opposed to older P-Type PERC) are naturally bifacial, meaning their rear side is already very efficient at converting light to energy. Most premium bifacial panels you see on the market today are built on an N-Type platform, combining the benefits of higher efficiency, lower degradation, and bifacial gain.

What Factors Determine Bifacial Gain?

This is the most critical technical section for any homeowner to understand. The bifacial gain is not guaranteed. It is a variable that depends entirely on four key factors of your installation. If these factors are not optimized, you will be paying a premium for a feature you are not using.

What is albedo and why does it matter?

Albedo is the single most important factor for bifacial performance. Albedo is a measure of how much light is reflected by a surface, with 0% being perfect black and 100% being perfect white. The higher the albedo of the surface under your panels, the more light will be reflected to the rear side, and the higher your bifacial gain.

This table illustrates how much albedo values can vary. This data is critical for estimating real-world performance.

Surface Material	Typical Albedo Value (% Reflectivity)	Impact on Bifacial Gain
Fresh White Snow	80 – 95%	Excellent (Can produce the highest gains)
White TPO Roofing / White Gravel	70 – 85%	Excellent (Ideal for flat roofs)
Light-Colored Concrete	40 – 60%	Very Good
Sand / Light-Colored Dirt	30 – 40%	Good
Grass / Vegetation	20 – 30%	Moderate
Standard Asphalt Shingle Roof	10 – 20%	Poor
Black Asphalt Pavement	< 10%	Negligible

How does mounting height affect bifacial performance?

Mounting height is the second most important factor. The rear side of the panel needs “room to breathe” to “see” the reflective light from the surface below. If a panel is mounted too close to the surface, it blocks its own light source.

• Flush-Mount (2-4 inches / 5-10 cm): At this height, which is typical for standard residential roofs, light diffusion is extremely limited. The bifacial gain will be minimal, regardless of albedo.
• Tilted Mount (1-3 feet / 0.3-1 m): This height, common for flat-roof or ground-mount systems, allows for excellent light diffusion and significantly boosts gain.
• High Mount (3-6+ feet / 1-2+ m): Ideal for ground mounts and solar carports. This height maximizes the “view” of the ground, leading to the highest potential gains.

How does tilt angle affect bifacial gain?

A steeper tilt angle generally increases bifacial gain. A panel tilted at 30-40 degrees exposes its rear side to a much wider angle of reflected light from the ground in front of it. In contrast, a panel mounted at a low 5-10 degree tilt (common on commercial flat roofs) will have a lower gain. This is why ground-mounted systems, which can be tilted to an optimal angle, are perfect for bifacial technology.

What is the impact of the mounting structure (racking)?

The racking system itself can block light from reaching the back of the panel. Traditional rails that run horizontally across the back of a panel can create significant shading and reduce gain. Installers must use racking systems specifically designed for bifacial panels, which typically use “clips” on the edges or a single, thin central rail to minimize rear-side shading.

Are Bifacial Panels Worth It for Residential Rooftops?

This is the key question for most homeowners. The answer is nuanced: for most standard, sloped-roof installations, no. For specific residential applications, absolutely yes.

Do bifacial panels work on a standard asphalt shingle roof?

No, the performance gain is negligible and not worth the extra cost. This is the most common misconception. A standard residential installation on a sloped roof (like asphalt shingles, tiles, or slate) fails the test of the two most important factors:

1. Low Albedo: Asphalt shingles are dark, with an albedo of 10-20%. There is very little light to reflect.
2. Low Mounting Height: Panels are mounted “flush” to the roof, leaving only 2-4 inches of space. This is not enough height for light to properly diffuse and reach the back of the cells.

In this scenario, you would be paying a premium for a bifacial panel but would likely see a bifacial gain of only 1-3%. A high-efficiency monofacial panel would be a far more cost-effective investment.

When do bifacial panels make sense on a residential roof?

Bifacial panels are an excellent choice for specific residential roofs that are not standard sloped asphalt. These include:

• White or Reflective Flat Roofs: If you have a flat residential roof covered in a white TPO, EPDM, or other reflective membrane (albedo of 70%+), bifacial panels are a fantastic option. When installed with a tilt-leg mounting system (giving them 1-2 feet of height), they can achieve significant bifacial gains of 10-15%.
• Reflective Metal Roofs: A light-colored or unpainted standing-seam metal roof can also have a high enough albedo to provide a modest gain, provided the panels are tilted and not mounted flush.

What about bifacial panels for residential ground-mounted systems?

This is the ideal residential use case for bifacial panels. A ground-mounted system optimizes all the key factors:

• Optimal Height: Can be mounted 3-6+ feet (1-2 m) off the ground.
• Optimal Tilt: Can be tilted at the perfect angle for your latitude.
• Controllable Albedo: The homeowner can control the ground surface. Laying down light-colored gravel (60-70% albedo) or (in some climates) just relying on snow (80%+ albedo) can produce massive bifacial gains.

Solar carports, pergolas, and patio awnings are also perfect applications, as the panels provide shade while the ground or patio beneath reflects light to the rear side.

How Do Bifacial Panels Compare to Monofacial Panels? (Pros vs. Cons)

While the focus is on energy gain, there are other important differences in durability and cost that homeowners must consider.

Pros of Bifacial Panels	Cons of Bifacial Panels
Higher Energy Yield (in correct applications): Can produce 5-30% more electricity than a monofacial panel.	Higher Upfront Cost: The panels themselves and the specialized racking are more expensive.
Greater Durability (Dual-Glass): Most bifacial panels are “dual-glass,” sandwiching the cells between two panes of glass. This is far more durable than a standard plastic backsheet and is highly resistant to moisture, PID, and weathering.	Heavier: Dual-glass panels are significantly heavier than monofacial panels, which can impact roof load limits and make installation more difficult and costly.
Longer Warranties: Due to their higher durability and N-Type cell structure, bifacial panels often come with 30- or even 40-year performance warranties, compared to the 25-year standard for monofacial.	Installation is More Complex: Installers must use specialized racking and be careful not to shade the rear side. This is not a standard “cookie-cutter” installation.
Better Performance: They are typically built on superior N-Type platforms, meaning they already have better temperature coefficients (work better in heat) and lower degradation.	Gain is 100% Variable: The performance boost is not guaranteed. It is entirely dependent on albedo, height, and tilt, making it harder to model savings accurately.

How Much More Do Bifacial Panels Cost in 2025?

Bifacial panels are a premium product. While the manufacturing costs have decreased significantly, you can expect to pay more for a bifacial system.

• Panel Cost: The panel module itself may only be 5% to 10% more expensive than a comparable monofacial panel (e.g., $0.05 to $0.10 USD per watt more).
• Installation Cost: This is where the real cost difference lies. A ground-mount, carport, or flat-roof tilt system is inherently more expensive in materials and labor than a standard flush-mount roof installation.

Therefore, a total bifacial system’s installed cost (in $USD or €EUR) might be 15% to 25% higher than a standard monofacial system, but this cost is for an entirely different, higher-performing type of installation. Authoritative sources like the U.S. National Renewable Energy Laboratory (NREL) have published extensive research on bifacial system performance, which confirms the critical role of albedo and installation factors. You can read an NREL overview here. Similarly, the IEA-PVPS program tracks global PV trends and notes the rapid market adoption of bifacial technology, particularly in utility-scale projects in regions like India, Türkiye, and the U.S. desert southwest, which helps drive down global costs. You can read their 2023 Trends report here.

In conclusion

Bifacial solar panels represent a superior and more durable generation of PV technology, but their primary benefit—bifacial gain—is unlocked only in specific installation scenarios. For a homeowner, the decision must be based on a clear-eyed assessment of your specific property.

Bifacial panels are likely NOT worth the extra cost if:

• You have a standard, sloped asphalt shingle or tile roof.
• Your installer plans to mount them flush (2-4 inches) to the roof.
• Your primary goal is the lowest possible upfront installation cost.

Bifacial panels ARE an excellent investment and worth the cost if:

• You are installing a ground-mounted system where you can optimize tilt, height, and the ground surface.
• You are building a solar carport, pergola, or patio cover.
• You have a flat roof and can use a reflective white membrane with tilted racking.
• Your priority is maximizing long-term energy yield and you value the 30+ year durability and warranty of a dual-glass, N-Type panel.

Before signing any contract, demand a transparent analysis from your installer. They must justify their choice of bifacial panels by providing a clear, data-driven estimate of your site’s albedo, the planned mounting height and tilt, and the resulting expected bifacial gain. Without this, you are simply paying a premium for a feature you may never use.