Always looking to become more green, California's latest regulations will make homes and buildings more energy efficient-- and more costly. Starting in 2014, buildings must have features like solar-ready roofs and sensor lighting systems.

Improved fans and windows that help control temperature are also highly recommended.

Many upgrades, like the windows, will be easily visible. Others, like hot water pipe insulation, will be hidden. And some homebuyers may not ever want solar power, as it's still pretty expensive. Even so, state energy officials say they have an obligation to require installation of these energy-saving features while the structure is being built.

"That's when it's the least expensive," says California Energy Commissioner Karen Douglas. "That's when efficiency is the most effective. It's far better than somebody coming back later and trying to retrofit the building."

While the rules have the support of some big stakeholders, like the California Building Industry Association, some industry groups worry the revisions will mean higher construction costs just as many Californians are reeling from the recession. In a statement to Fox News, the American Roofing Manufacturing Association claims the new technologies are based on "flawed data and poor science."

And Stephen Yurek, president of the Air-Conditioning, Heating and Refrigeration Institute, says there isn't enough oversight of the tough standards already in place.

"We'd like to see more being done in enforcing what's already out there then continuing to increase this stringency of the regulations," says Yurek.

Taking Fox News on a tour of a state-of-the-art house in Sacramento, Douglas argued the upgrades will save energy, and money, through lower monthly utility bills. She adds they will help ensure the lights stay on for all Californians.

"Our power plants don't have to run as often, we've been able to build fewer power plants. So we've had savings as well in our electricity system. It's been a tremendous benefit to the state," she says.

With solar-ready roofs now mandatory in next generation structures, the new standards should also benefit another green sector: the state's growing solar industry.