California regulators approve plan to mandate solar panels on new homes

California regulators on Wednesday approved a first-in-the-nation plan to mandate the installation of solar panels on all new homes beginning in 2020.

The move was approved with a 5-0 vote by the California Energy Commission, in what supporters of solar energy are hailing as a monumental moment.

“This is an undeniably historic decision for the state and the U.S.,” Abigail Ross Hopper, the Solar Energy Industries Association’s CEO said in a statement. “California has long been our nation’s biggest solar champion … now, California is taking bold leadership again, recognizing that solar should be as commonplace as the front door that welcomes you home.”

The regulation will go into effect once it receives its expected approval by the Building Standards Commission later this month.

And while proponents of renewable energy may be pleased with the decision, there’s mounting concerns that the requirement will only aggravate the state’s home affordability crisis, as the mandate is expected to add at least $10,000 in additional construction costs.

However, supporters argue that utility savings will balance out that cost in the long term.

“Adoption of these standards represents a quantum leap in statewide building standards,” Robert Raymer, technical director for the California Building Industry Association, told the commission. “You can bet every other of the 49 states will be watching closely to see what happens.”

But Republican leaders are already coming out against the decision, framing it as just the latest example of government overreach in Sacramento.

“That’s just going to drive the cost up and make California, once again, not affordable to live,” Republican Assemblyman Brian Dahle reportedly said of the dangers of the rules.

The mandate will apply to all homes, condominiums and apartment buildings up to three stories high — with exceptions for structures that are covered by shade.

According to the commission’s own estimates, the panels will cost homeowners around $40 a month, but save them about $80 a month on heating, air conditioning and other costs.

“This is great for wealthier homeowners, but for everybody else it’s one more reason to not go to California or to leave ASAP,” American Enterprise Institute economist Jimmy Pethokoukis said on CNBC Wednesday.

More broadly, the move is part of California’s plan to have all residential buildings be “zero net energy,” which means that the the total amount of energy used by the building is the same as the amount of renewable energy it creates.