Net-zero buildings that produce as much energy as they consume may be about to hit the mainstream in California, where most new homes and multi-residential structures up to three stories high will be equipped with rooftop solar panels beginning next year.
The state is expected to add as many as 100,000 new net-zero homes per year, featuring local energy production and airtight construction to optimize energy efficiency.
So far, there are only about 5,000 single-family and about 7,000 multi-family net-zero homes across the entire United States, according to the U.S. Net-Zero Energy Coalition. But “if you buy a new house in California within the next few years, there’s a good chance it will be built along similar lines,” CNBC reports, under new rules the state instituted in December. “Depending on the specifics of the design and the residence’s energy consumption pattern, solar panels could produce all the electricity needed for the home.”
CNBC’s list of the top ten net-zero municipalities includes four in California, with Vancouver, British Columbia placing second. While Tucson, Arizona and South Miami, Florida already have building code requirements that support net-zero construction, California is the first to build the standard into its state-wide code.
“California by itself is one of the largest economies in the world,” said Rocky Mountain Institute principal Jacob Corvidae. “What happens there has some impact, and it’s going to be an impact that has an effect on the rest of the country. Because they’re going to be figuring out ways to make solar cheaper, and that scale will help bring down the cost.”
CNBC explains that “net-zero energy and zero energy-ready homes—which can be zero energy if solar panels are installed or their capacities are increased—are built to be more energy-efficient than a typical building. This includes adding extra insulation, high-quality windows, LED lighting, low-flow water fixtures, heat-reflecting roof tiles, and energy-efficient appliances that, when combined, reduce the amount of energy the house consumes.” The accent on airtight roofs, walls, windows, and foundations also allows for “better temperature regulation, low-humidity, less noise, and minimize[d] exposure to dangerous pollutants,” the network adds, citing Chief Architect Sam Rashkin at the U.S. Department of Energy’s Building Technologies Office.
Regulators in California estimated the net-zero mandate would add US$40 per month to the average monthly mortgage, but save $80 per month on heating, cooling, and lighting over a 30-year term. “The up-front cost to a single-family house will be approximately $9,500 with savings of $19,000 over 30 years,” CNBC states.
“It’s the same thing as asking for a roof rack on your car. You’re going to pay extra,” said Net-Zero Energy Coalition board member Ann Edminster. But she argued “that people shouldn’t be thinking of the up-front costs in isolation,” CNBC adds. “Homebuyers can make decisions in a house’s design that offset the additional costs for net zero-energy upgrades, such as sacrificing decorative housing elements.”