Roof shading and solar panels: how much does shade matter?
Shade is one of the biggest reasons two similar homes get very different results from solar.
Why a little shade can cost a lot
Panels are wired in groups. With a traditional string inverter, a shaded panel can drag down the output of others in its string. Microinverters or power optimizers let each panel work independently, which limits the loss but adds cost.
Shade changes through the year
In BC and Alberta the winter sun is very low, so a tree or building that doesn’t shade your roof in June may shade it all day in December. Fortunately, winter produces only a small share of yearly output anyway; summer shade matters most.
Trees grow
A tree that barely touches your roof today may shade it in ten years. Consider whether trees (yours or a neighbour’s) will be trimmed, and whether you’d want to.
How shade is measured
Installers use site visits and software. Our reports use Google’s Solar API, which models sunlight on each part of your roof from aerial imagery and 3D data including nearby trees and buildings, and places panels where the sun is best. The imagery has a capture date, so check whether anything has changed since.
Find out for your own home
Your roof, your bills, your utility’s rules: a clear answer in a $4.99 report, with no sales calls.
Check my roof — free