Some panels come with self-adhesive backings, but reviews, like those for the JOLOV 3D peel-and-stick PE foam wall panels, say they can sometimes leave behind residue or even pieces of the panel.

Top: A stack of solar panels await installation at a house. Above: Solar Optimum installers Karen Mkhitaryan (cq), left; Armen Gharibyan (cq) and Hrach Poghosyan (cq) install a main service box ...