A first-in-the-nation law requiring new homes to have rooftop solar panels takes effect Jan. 1. State building codes also require better insulation and air filtration for new homes, and homeowners get additional incentives to install batteries to store solar power.
Another major new policy, taking effect in a handful of jurisdictions, involves reducing natural gas use: In the Bay Area, if you’re building a new home in Berkeley, San Mateo, Menlo Park, San Jose or Marin County, you either won’t be able to install gas appliances, or you will have to make your home more energy efficient if you do. Similar laws in 14 other Bay Area cities await California Energy Commission approval.
From the article: