The simple answer is it depends.
Ran across this article by Margaret Collins over on the www.getsolar.com blog about how much it costs to install a solar system. http://bit.ly/3pLHsE. This article goes over the basic factors with links to more detailed Sounds like basically, “it depends.” She covers issues that deal with which state you live in, the kind of roof, your site, and your energy use.
Over on EcoDepotUSA.com there is a solar/wind calculator in the right hand column that can also help your estimate the cost of your solar or wind installation. You start out by typing in your zip code, then fill in the blanks about how much electricity you’re currently using.