For what it is worth I do to. It is amusing to get to tell them I already have solar at which point they look up and then walk away. But think about it... What kind of margin pays to have someone walk door to door? That is the kind of waste that the system has not yet rung out and why residential costs don't seem to be going down as much as they should. As long as all of the installers don't drive their costs down they all get to enjoy growing profits!
> What kind of margin pays to have someone walk door to door?
If I had to guess, the door-to-door folks are probably lead gen companies that sell leads to solar installers. The economics work out largely because solar installations are such a big ticket item that good leads can demand a nice sum. As a thought exercise, Amazon will pay in the range of 5% to affiliates. If you buy a $100 pair of shoes on Amazon, that will net the affiliate $5. If a solar lead gen gets the same rate, then a single $30k system will earn them $1500. So that salesman only needs to sell a few systems per month to cover salary. Hence the door-to-door.
Also, it's worth mentioning that the residential solar market is pretty cutthroat. Quite a few companies have recently filed for bankruptcy. Part of the reason lead gen and marketing costs are so high is because these companies are fighting tooth and nail for customers. I am pretty sure most installers would love to cut back on that spending, but without it their business would collapse.