SACRAMENTO — Newly sworn-in state Sen. Scott Wiener, D-San Francisco, plans to introduce legislation Monday requiring all new construction in the state to include solar panels.

The bill expands on a San Francisco city ordinance Wiener wrote while on the Board of Supervisors that requires solar panels to be put on new construction within the city, including residential and some commercial buildings. The city ordinance was passed last year and applies to any project that receives building permits after Jan. 1.

San Francisco was the first major city in the country to require that solar panels be installed on new buildings and homes. California already requires 15 percent of the roof area on residential homes and small and midsize commercial buildings with 10 floors or less to be “solar ready,” meaning the area must be free of shade and other obstructions.

Wiener’s bill, like the San Francisco ordinance it’s modeled after, would require builders to install solar panels on 15 percent of roofs. The solar could either be purchased by builders or a third party could own and maintain it. Wiener said current law ensuring new buildings are “solar ready” isn’t enough.

“We figured if you are going to make it solar ready, just put the panels on and start out with solar energy integrated into the building,” Wiener said. “People are frustrated with the slow pace of moving toward renewable energy, and people have a sense of urgency that we don’t have time to waste. We need to move away from a carbon-based economy.”

While the San Francisco ordinance passed unanimously, Wiener’s bill is likely to encounter resistance in Sacramento’s Capitol. California builders say the state’s fees and others costs for building homes are already high. And the cost of adding solar will probably be passed along to buyers in a state with skyrocketing housing prices. And that could price some people — particularly in low-income areas — out of the housing market, warned critics, who declined to speak on the record about the proposal until the bill’s language is made public.

The average home in California costs $440,000, which is 2½ times the national average of $180,000, according to the nonpartisan Legislative Analyst’s Office, which released a report in 2015 on the state’s high cost for housing.

Wiener said he doesn’t see the cost of solar being a deterrent.

“It’s not a significant cost,” he said. “It either pays for itself over time or you don’t even have to own the panels. You can have a third party come in and own and maintain the panels. That’s why we got little pushback from the development community in San Francisco.”

Three other cities also require solar on new buildings, including Lancaster, Sebastopol and Santa Monica. Lancaster, which is located in the western Mojave Desert in Los Angeles County, was the first city in the state to require solar on new construction in 2013.

“I think we can simultaneously build great housing that is environmentally responsible,” said Todd David, executive director of San Francisco Housing Action Coalition. David previously worked as political director for Wiener’s Senate campaign.

Melody Gutierrez is a San Francisco Chronicle staff writer. Email: mgutierrez@sfchronicle.com Twitter: @MelodyGutierrez