That reroofing problem worries me, my house is about the age where a new roof will be necessary soon. I was hoping that I would be able to install thin film PV shingles when the time came. Maybe they will treat it as a "one-time move" situation and reinstall after the roofers do their job, with no charge.

According to their literature, they try to design a system which will supply the number of kilowatts you use over a year. My house has a heat pump and I don't know if there is enough room on the roof to provide that much power over a year.

Could they be making money by selling power in the day and buying it cheaper at night?