Due to their dark color, solar panels heat up in the sun. In the winter, warm panels can sometimes provide a welcome respite for cold critters like squirrels and birds.
Animals nesting under your panels isn't ideal, as they can damage or dislodge wiring, which can contribute to panel outages and therefore production issues.
If you live in a neighborhood with a lot of local wildlife, adding a critter guard could be a good investment against future repairs--especially if your area gets cold in the winter.
A critter guard functions as a netting or grate to close off the area between your panels and the roof.
The critter guard that Project Solar sources, by HEYCO. For information on the wire clips used, see this link.
For regions with less wildlife and temperate climate, critter guards are usually unnecessary.
Project Solar does not include critter guards by default, but we do offer them as an optional add-on. The cost of this service is $0.15 per watt.