Solar Shading Loss Estimator
Estimate how much energy and revenue you're losing from shading — and whether power optimizers are worth it.
How Solar Shading Loss Works
Why Shading Hurts More Than You Think
In a traditional string inverter system, all panels in a string are limited by the weakest panel. If one panel is shaded to 50% output, it can drag down the entire string — meaning 20 panels can perform like 10. This is called the "Christmas lights effect."
How This Estimator Calculates Loss
We estimate the shading loss by combining two factors: the proportion of panels shaded and the hours of shading relative to total peak sun hours. The result is the percentage of your annual production being lost. The dollar loss is that percentage applied to your full annual production valued at your electricity rate.
Power Optimizers and Microinverters
DC power optimizers (SolarEdge, Tigo) and microinverters (Enphase) allow each panel to operate independently. If shading affects only some panels, these devices can typically recover 25–30% of the shading loss by preventing shade from spreading across the string. They add $500–$2,000 to system cost but can pay for themselves quickly in high-shading situations.
When to Act
If your shading loss exceeds 15%, it's worth consulting with your installer about optimizers, rerouting string configurations, or in extreme cases, relocating panels. Even trimming trees can dramatically improve output.