In the past, all sales were done by the installers. However, residential solar customer acquisition is both difficult and expensive. There is now a growing group of originators (sometimes called resellers), who sell solar on behalf of an installer or financier.
These include companies like Evolve Solar, Blue Raven Solar and LGCY Power. Because of this, the seller can be the hardest player to identify, as the installer and/or financier ultimately receive the credit for the installation