The California Energy Commission (CEC) updated building energy efficiency standards

that the CEC says will cut regulated energy use in new homes by 28 percent and save consumers $31 a month compared to houses built under the current energy code. The new standards also set the stage for zero net energy new homes in the state within five years. A zero net energy home, is a home with zero net energy consumption, meaning the total amount of energy used by the home on an annual basis is roughly equal to the amount of renewable energy created by the home.
Known as "Title 24," the standards will go into effect on January 1, 2017, and set minimum energy-saving requirements for new buildings and renovations that will reduce energy used for lighting, heating, cooling, ventilation, and water heating.
With tens of thousands of homes built every year in California, the energy savings will add up to big environmental benefits: for buildings constructed and retrofitted in 2017 alone, the CEC found that standards will cut energy use by about 281 gigawatt hours of electricity and 16 million therms of natural gas per year, reducing harmful carbon dioxide pollution emissions by about 160,000 metric tons per year. After 30 years of construction, the CEC estimates that these savings will add up to the equivalent energy use of twelve large power plants.