A ton of home solar companies, the kind that do door-to-door, are scammy for sure. The solar system you end up with is generally fine, but the sales process has two main problems. First, they want to get you in on some kind of hyper-aggressive financing or indirect ownership scheme, which means your savings are basically negated and you ownership is tenuous or nonexistent - not something you want for hardware permanently affixed to your roof and electrical system. Second, they are usually sales-only companies that contract out to a third party builder. That means that once you buy from them (at an inflated rate so both companies can profit) they cut and run and you're left with a totally different company to actually complete the work.

My company does residential as well as commercial, but we don't really have any outside sales pipeline for that. People call in, we negotiate a price, and then we build the system for them. We don't do any financing on that front - you figure out how to pay for it, you own it, we do maintenance. That's relatively unusual.