Mark Bortman of Exact Solar in Yardley, Pa., says having leased solar panels on a roof can add an extra step when selling a house. He says typically a buyer will assume the remainder of the lease, but that requires a credit check and some paperwork Jeff Brady/NPR hide caption

itoggle caption Jeff Brady/NPR

Businessman Tom Wolf talks to U.S. Rep. Allyson Schwartz before the Pennsylvania Democratic Gubernatorial Primary Debate last week in Philadelphia. Michael Perez/AP hide caption

itoggle caption Michael Perez/AP

A Philadelphia Gas Works employee replaces old steel and cast-iron pipes with new plastic pipes that are less likely to leak. Jeff Brady/NPR hide caption

itoggle caption Jeff Brady/NPR