Is Solar Panels a valid equity add?

[James Pegues]

I continue to have solar salesman come by my primary residence pitching their solar systems. There was one guy today that struck me as different as he mentioned it would add an average of 4% value to my property. Is there any truth to this or is it just a sales tactic to help sell the system? Any appraisers here that could give more insight on this? Also, if it's financed, would I have to pay it off fully if a buyer didn't want to assign the note for the system? The quote I got is good for 7 days so I decided to ask some professionals to make sure I won't lose anything when it comes time to sell. Thanks!!!