Would a quick estimate help?
Shading: why one shadow can matter
Shading is the fastest way to ruin an otherwise great design. The impact depends on wiring topology and whether you have module-level power electronics (MLPE).
It changes how current flows through a string and triggers bypass diodes.
String behavior
In a series string, current is shared. If one module is shaded, the string current is limited unless bypass diodes activate (which reduces voltage and power).
Bypass diodes protect the module by routing current around shaded cell groups—but you still lose output.
Takeaway: shading patterns (morning vs afternoon) and partial shading matter more than people think.
- Trim vegetation (sometimes the highest return on investment upgrade)
- Use microinverters/optimizers if roof planes vary or shading is complex
- Layout strategy: keep shaded modules in their own string where possible
What to ask your installer
Shade report
Ask for a shade analysis tool output and annual shading loss estimate.
String map
Request a drawing showing which modules are on which string/MPPT.
Performance assumptions
Ask for PR assumptions and how they translate to annual kilowatt-hour.