I know enough to be dangerous. I would want to know how the solar company buys and sells its power. The solar power is A) gov't subsidized and B) generating power during peak usage when the power is worth more. Thru the subsidies and rate structure the solar company is able to sell power from the panels on your house back to the grid at significantly higher rates do to peak demand and when your house is probably at a lower usage. It then has to buy power off the grid when it is dark, the power is cheaper then. That's how they make their money, so long as your panels are making excess power during the peak that they can sell. I would want a solid estimate of what the panels your house can accommodate will produce, and how many months of the year it will benefit you. I would also want to know the risk of the gov't subsidies running out, these companies cannot exist without them. In the NE you need a good southern exposure and maybe half the year it is going to net you something. If you buy your own panels, you will not be able to make the same money as these solar companies can, and it will take you a long time to get any pay back unless you can get completely off the grid.