How we estimate, and what we won't fake

Conservative gain ranges, never single numbers

Bifacial gain — the extra energy from the panel's rear face — is real but commonly exaggerated. In favorable ground-mount conditions it's typically an estimated 5–15%, and in exceptional high-albedo conditions — fresh snow, bright white surfaces — gains can approach 25%. On flush roof or flat RV mounts it can be close to zero. Our calculator therefore always returns a range, built from two conservative factors:

• a surface potential for the ground behind the array (grass, concrete, white gravel, reflective roof, snow), reflecting how much light it bounces back; and
• a mounting realization for how much of that potential a given mount actually captures — high for tilted ground mounts, low for flush roof and flat RV mounts.

Energy estimates apply a standard, slightly conservative performance ratio (0.77) to account for ordinary system losses such as inverter, wiring, temperature, and soiling. We present the result as a rough planning guide, not an accurate forecast.

Note on our coefficients:the surface and mounting factors, and the per-state peak-sun-hour figures, are currently conservative engineering estimates pending formal source review against references such as published bifacial field studies and NREL's PVWatts. We'd rather under-promise than over-promise while that review is in progress.

No invented prices

We do not display prices. They change constantly, vary by retailer and region, and some affiliate programs prohibit showing them. When a retailer link is live, we send you to the store to see the current price directly.

Verified facts are kept separate from affiliate routing

In our data model, a product's verifiable specifications (wattage, cell type, bifaciality factor, warranty) are stored separately from its affiliate routing(which retailer, which tracking parameters). That separation means a commercial relationship can never quietly change a stated fact, and we can add or swap affiliate programs without touching the product information you read.

We don't claim hands-on testing unless we test

We will never publish "we tested," star ratings, or "best overall" badges for products we haven't genuinely evaluated. Where we haven't done first-party testing, we say so and frame guidance as what to look forrather than a ranked verdict. For that reason we also avoid Product, Review, and AggregateRating structured data, which would imply verification we don't have.

Why bifacial gain depends so heavily on conditions

The rear face can only generate from light that reaches it, so a handful of physical factors dominate the outcome:

• Rear-side exposure & mounting height — the more open sky and clearance behind the panel, the more reflected light it sees. Flush mounts block most of it.
• Tilt — angled panels expose the rear face to reflected ground light; flat mounting largely defeats the benefit.
• Ground reflectivity (albedo) — white gravel, snow, and reflective membranes bounce far more light than grass or dark asphalt.
• Shading — partial shade on the front or rear disproportionately cuts output.
• Row spacing— tightly packed rows shade each other's rear faces and reduce gain.

Corrections

If you find an error, tell us at hello@bifacialpanels.comand we'll review and update. BifacialPanels provides general educational information, not engineering or installation advice.