California became the first state on Wednesday 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 Wednesday 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. Solar companies including First Solar Inc., Sunrun Inc., Vivint Solar Inc. and Enphase Energy Inc.