In California, installers are needed to have possibly a typical contractors license or a C-46 Solar Contractors License. This license handles installations for photovoltaic systems, solar drinking water and House heating, and solar pool heating. Other certifications you should watch out for, none of which can be legally demanded but https://solarpanelsinstockton.blogspot.com/2025/10/go-green-and-save-big-with-best-solar.html