EnergySage, Google, Reviews.io, Reddit, and Yelp can all be good places to look for reviews. Certification isn't a firm requirement for EnergySage installers, but it's highly recommended. If the installer started working in the solar industry before NABCEP was formed in 2002 and has a long (and positive) track record, we may still allow them to join our Marketplace. We also recognize installers annually for standout customer service through the EnergySage Installer of the Year awards. It depends on where you live and what type of panels you're installing. With the winter months in California being very mild, you have significant leeway to install your panels, though they won't reach peak performance until summer arrives.