I reposted this in the Renewable Energy forum

I'd be weary of signing a 20 year contract with a company that may not be around in 20 years. (Https://www.technologyreview.com/s/601217/watching-sunedisons-collapse-solar-industry-resets/) Sounds like a type of subprime lending similar to the housing crisis of 2008. You're better off buying the system with no out of pocket and financing for 10-15 years. That way you own the system after you're done paying it off and if you do your research and get a high quality system, it will work for 25-40 years. Your home value also goes up when you buy a system, not lease and you get the 30% Federal Tax Credit!