California Votes to Require Rooftop Solar Power on New Homes (1)

California became the first U.S. state to require solar panels on almost all new homes, sending the clearest signal yet that rooftop power is moving beyond a niche market and becoming the norm.

Most new homes built after Jan. 1, 2020, will be required to include solar systems as part of energy-efficiency standards adopted May 9 by the California Energy Commission. While that’s a boost for the solar industry, critics warned that it will also drive up the cost of buying a house by almost $10,000.

The move underscores how rooftop solar, once a luxury reserved for wealthy, green-leaning homeowners, ...