Before you decide
How much do trees and shade affect solar panels?
The short answer
More than the area covered would suggest, because panels in a conventional string are electrically linked and the weakest one constrains the others. Module-level electronics — microinverters or power optimisers — reduce that effect substantially, and they do not recover the energy the shaded panel never produced.
What to establish before a design is drawn
- What shades the roof, and at what times of day and year. Winter shadows are much longer than summer ones.
- Whether the obstruction is permanent — a chimney, a neighbouring building — or manageable, like a tree that can be pruned or removed.
- Whether the design uses string inverters, optimisers or microinverters, and why that choice was made for your roof.
- Whether the production estimate models the shade or assumes an unshaded roof.
Trees are a decision, not a detail
Removing a mature tree to improve solar output is a real trade-off involving shade on the house, the character of the property, and in many municipalities a permit. It is worth deciding deliberately rather than being talked into or out of it by whoever is selling the system.
Ask to see the shade analysis, not just the annual production number it produced. A proposal that cannot show its shading assumptions is a proposal whose headline figure cannot be checked.
Also asked
Do microinverters fix shading?
They stop one shaded panel dragging down a whole string, which is a real and significant improvement. They do not make a shaded panel produce. If a roof is heavily shaded, the honest answer is that a smaller array on the unshaded part may be better than a large one across all of it.
General information about solar and about hiring, not advice about your roof or your tax affairs. Incentives, net metering and contractor licensing are set federally, by state, and by your utility, and all of them change. The authority that publishes the rule is the current answer.