Bifacial panels have become common in Pakistani markets, often sold with the promise of “extra power from the back.” There is some truth in that, but how much you actually get depends almost entirely on how they’re installed.
- Bifacial panels collect some light reflected onto their back side.
- Extra gain is usually modest, often single digits to low teens in percent.
- They need height and a light-coloured surface below to shine.
- Flush-mounted on a dark roof, the benefit is small.
How bifacial panels work
A normal panel has a solid white or black backsheet. A bifacial panel has glass, or a transparent backsheet, on the back, so light reflected from the roof or ground can hit the rear of the cells. The front still does most of the work. The back adds a bonus.
How big is the bonus?
Manufacturers quote “bifaciality,” often around 70 to 80%, meaning the back side is that efficient compared to the front. But the back gets much less light. Real gains in typical installations are usually in the range of a few percent up to around 10 to 15% in ideal conditions.
What makes bifacial work well
- Height: panels raised at least a metre or more above the roof let reflected light reach the back.
- Bright surface below: a white-painted roof or light-coloured tiles reflect far more than dark concrete.
- Open structure: rails and beams that don’t block the back of the panel.
- Elevated structures over car porches or open terraces are a natural fit.
When they don’t make much difference
Panels mounted low and close to a dark roof, or with a solid structure behind them, get very little rear light. In that case you’re paying for a feature you won’t use much. A good standard monofacial panel would do almost the same job.
A cheap trick to boost them
If you already have raised bifacial panels, painting the roof underneath with white heat-reflective paint can increase rear-side gain and, as a bonus, keep the floor below a bit cooler in summer.
Weight and handling
Glass-glass bifacial panels are heavier than standard ones. Make sure the structure is rated for the weight and wind load, especially on elevated frames.
Whatever panels you choose, the inverter still needs to match their voltage and current. Read what MPPT means before finalising a string.
Planning an elevated structure?
Tell us the height and roof finish. We’ll tell you whether bifacial is worth the extra.