California requires solar power on all new homes starting in 2020

California has voted to require solar panels on new homes and low-rise apartment buildings built after 2020.
The California Energy Commission estimates they would add an average $10,500 in construction costs for a single-family home but generate about $16,000 in energy savings. The standards also include requirements around ventilation and indoor air quality.
About 117,000 new single-family homes and 48,000 multi-family units will be built in 2020.