According to a recent study led by Lawrence Berkeley National Laboratory, home buyers are willing to pay more for homes with host-owned rooftop solar systems. As common-sense as these findings might seem to solar insiders, the figures provide a benchmark and some confidence for realtors and appraisers. That's the true audience for these calculations. As the number of solar homes grows, the question of the real value of a used solar system is going to come up more and more. More than half a million U.S. homes had PV installed in the U.S. by the end of 2014. "As PV systems become more and...