The Value of Solar PV / by Jon Gardzelewski

Each watt of Solar PV you install will add approximately $3 to your home’s value ($4 if you live in California), according to a 2015 report from the Lawrence Berkeley National Lab.

And a different study concludes high-performance homes marketed with green features sell for 3-4% more than comparable homes without green features. 

Read the full report here:
"What is Green Worth? Unveiling High-Performance Home Premiums in Washington, D.C." (pdf)