California this week became the first state in the nation to require all new homes to have solar power. The mandate, unanimously approved by the five-member California Energy Commission on Wednesday, is set to take effect in two years and is expected to add between $8,000 and $12,000 to the cost of a new home.

As The New York Times highlights, the new requirements will force builders to either make individual homes available with solar panels or build a shared solar panel array to serve a group of homes. If rooftop panels are chosen, they can either be rolled into the price of a home or offered through a monthly lease program.

The Energy Commission estimates the requirements will add about $40 to the average 30-year mortgage but save consumers as much as $80 per month on heating, cooling and lighting bills.

The plan will require new homes to have a system capable of generating a minimum of two to three kilowatts which will largely be dictated by the size of the home. As The Times notes, typical residential solar arrays are often two to three times that size and can sometimes generate enough to feed the grid.

California on average sees the construction of about 80,000 news homes each year.

For a state that is already suffering from a shortage of affordable housing, it’s sure to be a hot-button issue among locals.