No outward sign distinguishes it from the other homes taking shape on this street of new construction teeming with work crews. Two stories, with a two-car garage; a shaded front porch offers shelter from the blazing sun.
But this particular house is an experiment. And it could represent California’s future.
If all goes as planned, the home will generate as much electricity as it pulls from the grid over the course of a year, achieving a status known as “zero net energy.” Within four years, California officials want all new residential construction in the state to consist of zero net energy homes — a tall order.
Designed by the Pulte Group development company, the Brentwood house uses two small solar arrays to generate electricity and highly efficient lights and appliances to conserve it. But the house looks and feels like a typical three-bedroom, two-bath home, rather than a test bed for new technology.
“Pulte is going to help make this normal, where it isn’t something weird that causes 100 people to come out and look,” said Drew Bohan, chief deputy director of the California Energy Commission. “It’ll just be normal. That happened with solar; it’ll happen with this.”
It was also designed to be mass-produced. Although some of its technologies are new, it is a model that can be replicated again and again — or “scalable,” in a term the builder is borrowing from Silicon Valley.
“Everything we put into the house, we put here because it’s scalable,” said Brian Jamison, Pulte’s national purchasing director.
For now, it’s still a rarity. Although interest in zero net energy buildings — both residential and commercial — has been rising for years, fewer than 200 had been built nationwide by last year, according to a list compiled by the New Buildings Institute.
And yet, California is counting on zero net energy buildings as part of the larger fight against climate change.
The state has set a nonbinding goal that by 2020, all new single-family homes and new apartment buildings three stories or smaller will be able to produce as much energy as they consume over the course of a year. All new commercial buildings should meet the same standard by 2030.
“We’re not going to solve our climate and resources challenges if we don’t start building homes like these,” Bohan said.
The Brentwood home generates electricity through a pair of solar arrays supplied by San Mateo’s SolarCity. On a typical summer day, those arrays produce more electricity than the house needs, feeding the excess to the grid. At night, the house relies on the grid for power. Pulte chose not to equip the home with a battery that could store excess solar energy for use after dark.
The house relies heavily on sensors and automated systems to trim energy use. When direct sunlight strikes the windows, shades lower automatically, although the resident can choose to raise them again.
A smart thermostat from Lennox learns the resident’s habits and, when synced with a smartphone, automatically turns down the air conditioning when the resident leaves the house. The thermostat can also tell when the resident, and his phone, is approaching the home at the end of the day and turn up the AC accordingly.
A tank-less water heater from Rinnai, combined with a pumping system, saves energy and water. The resident activates it by pushing a button in the bathroom or kitchen. Within about 10 seconds, the system will heat the water and pump it to the faucets. Cold water sitting in the pipes gets pushed back to the heater. There’s no need to let the faucet run until the water warms up.
“You’re not wasting one drop of water waiting for it to get hot,” Jamison said.
One of the home’s biggest energy-saving features may also be one of the simplest. Instead of placing insulation on the floor of the attic as builders typically do, the insulation is “cathedralized” — installed under the roof. That keeps the attic from heating up. And because the air-conditioning ducts run through the attic, keeping the ducts cool means the air conditioning doesn’t have to work as hard as it otherwise would.
Pulte won’t say how much the house cost to build, noting that it’s a prototype.
“We’ll start talking about pricing once we’ve built more of these,” Jamison said.
The company will, however, put the Brentwood house up for sale at the end of the month. And Pulte plans to stay in touch with the buyers after the sale, gathering details about how well they like the energy-saving appliances and home features. Their feedback will help refine the next zero net energy homes that Pulte builds.
The state, meanwhile, may have a hard time meeting its 2020 goal. But Bohan said it’s not impossible. The technology to make zero net energy homes exists and is getting cheaper with time.
“I don’t think it’s some crazy notion,” he said. “It’s ambitious, but it’s doable.”
©2016 the San Francisco Chronicle Distributed by Tribune Content Agency, LLC.