A little bit of shade doesn't cause a little bit of production loss — the relationship is much less forgiving than most people expect.
Shading loss isn't proportional to shaded area
Solar cells are wired in series within a panel, and panels are often wired in series within a string — a single shaded cell can throttle the output of the whole chain it's part of, not just the fraction of area actually in shadow. This is why a small shadow from a chimney or tree branch at the wrong time of day can cost far more production than its physical size would suggest.
Estimate your specific situation with the shading loss calculator rather than eyeballing it from how much shadow you can see.
String inverters versus microinverters
A string inverter's output is limited by its weakest connected panel — shade one panel, and it drags down the whole string's production. Microinverters or power optimizers isolate each panel, so shading one doesn't affect the others. Whether that upgrade is worth the extra cost depends entirely on how much shading you actually have — see the microinverter vs string inverter calculator to check the real payback for your roof.
Time of day and season both matter
A tree that shades panels only in early morning or late afternoon costs much less than one that shades midday sun, since midday typically produces the most energy. Seasonal sun angle changes also shift which obstructions matter — a tree that's no issue in summer can cast a longer shadow across panels in winter.
Not all shading is a lost cause
Trimming a specific problem branch, or accepting a small unavoidable loss from a chimney, is often more cost-effective than paying a large premium for microinverters to solve a minor shading issue. Run the actual numbers before assuming the more expensive equipment option is worth it.
Frequently asked questions
How much production can a single shaded panel really cost?
On a string inverter system, a single significantly shaded panel can drag down the output of its entire string, not just its own share — the loss is often disproportionate to how much of the array is actually shaded.
Is it worth cutting down a tree for solar production?
It depends on the tree's value versus the production loss — for a tree causing meaningful midday shading on a significant part of the array, it's often worth evaluating; for minor early-morning or late-afternoon shade, it may not be.