Anyone could do this by hiring a roofer for a half day ($1,000) and an electrician for a half day ($1,000). You'd add about $1,400 to your net out of pocket and push your break-even out to about 4 years.

The real cost is a "sign-on-the-dotted-line" service where you pay a company to take all the hassle of buying the parts and assembling the crew. That will cost you about another $7,000 ($10,000 before tax rebates) and push your break even to around 8 years. I don't recommend this option