A Glimpse Toward the Future: PulteGroup Builds Prototype Zero-Net Energy Home in California

Fine-looking home design with three wooden pillars resting on marble concretes, a lawn and two small windows on the roof.

A rendering of PulteGroup’s prototype zero-net energy home in California, which shows the home without solar panels. Expected to be be complete in May, the home will be a chance for the company to develop zero-net energy homes on a large scale.

How would you like to live in a home that doesn’t cost you anything in energy bills?

PulteGroup, a major national homebuilder head- quartered in Atlanta, is building a prototype zero-net energy (ZNE) home in the company’s Botanica community in Brentwood, Calif.

ZNE homes, which produce as much energy from renewable sources as they consume, aren’t new. In fact, builders have constructed one-off ZNEs in cities all around the United States.

The unanswered question has been whether they can scale up the ZNE concept to build these homes in the hundreds instead of one at a time.

“We wanted to demonstrate proof of concept for a zero net home in a production environment,” says Brian Jamison, PulteGroup’s national procurement director, who is overseeing the home’s design.

Energy-Efficient Features

Pulte’s prototype ZNE home has two stories with three bedrooms and two-and-a-half baths in 2,343 sq. ft. of space, plus a two-car garage.

Brentwood is located 27 miles west of Stockton and 55 miles east of San Francisco. Other Pulte homes in this community have base prices of $495,990 to $656,370.

Those particulars aren’t nearly as interesting as the home’s extensive energy-efficient features, which aim to help it achieve zero-net status.

Top of the list — and top of the house — is a new type of “cathedralized” insulation from Owens Corning. This insulation is installed under the roof instead of on the attic’s floor to reflect heat away from the house before it gets in and turns the attic into a partially conditioned heated or cooled space. Jamison says this approach “increases the efficiency of (the HVAC) equipment.”

The Lennox heating and air conditioning system that Pulte selected has a high-efficiency heat pump, which doesn’t burn fossil fuels, so no volatile organic compounds (VOCs) are emitted when it’s used. The heat pump has a Seasonal Energy Efficiency Ratio (SEER) rating of 19 and multi-speed motors, which help to circulate air in the home. The higher the rating, the higher the efficacy of the system. 

The home’s fresh air induction and exhaust system uses a pleated Minimum Efficiency Reporting Value (MERV) 16 air filter. This filter is 5.5 inches thick and needs to be replaced only every nine to 12 months.

The system is controlled by a Lennox Wi-Fi-enabled iComfort thermostat. The Pulte prototype ZNE home also has LED lighting, Whirlpool Energy Star appliances, an electric induction cooktop and an integrated on-demand Rinnai tankless gas water heater.

The home isn’t on the electric grid, so power is available even on cloudy or rainy days. The prototype does not have a house battery.

By the way, “zero net” is sometimes called “net zero.” The term is so new there’s not yet a broad consensus as to which usage is correct. Jamison says “zero net” is typically used in California.

South-Facing Home

One of PulteGroup’s most exciting energy-efficient features, a 4.6-kilowatt Solar City solar power system, will be not inside the home, but on the roof.

Jamison says most ZNE homes need to generate 6 to 9 kilowatts of power and that requires an array twice as large as what Pulte has planned. Achieving zero-net energy with only 14 solar panels is “pretty spectacular,” Jamison says. 

What’s more, the house faces south and its solar panels will be visible on the street side of the home. The panels and mounting brackets are all black, so they blend seamlessly into the environment.

“Architecture is extremely important in this home,” Jamison says. “Pulte spends a lot of time and energy building neighborhoods that we think are beautiful and homes that are beautiful. I wanted to make sure that the aesthetics translated in the zero-net energy prototype.”

Feedback Loop

While the prototype is still only one house, Jamison says a key part of Pulte’s plan is to solicit feedback from manufacturers and local building trades with a view toward building a second, even better prototype and eventually entire communities of ZNE homes. 

“We’re documenting what’s working well and what could use some continuous improvement and we’re feeding that back into the process for future net-zero homes that we’re going to build,” Jamison says.

The current construction is due to be completed in mid-May. After that, the home will be marketed and sold.

“The entire process is meant to gain feedback” Jamison says. “We want Realtor feedback and consumer feedback. We’re going to have a month of marketing when the home is complete and then we’re going to put the home up for sale.”

The marketing activities will include open house events typical of builders’ model homes.

After the home is sold, Pulte will continue to monitor how the buyer’s experiences living in the home compare with the computer-modeled predications. The buyer will be asked to provide additional feedback about the energy-saving features for one year.

Jamison says the Pulte ZNE home prototype demonstrates innovation, concern for the environment and a need to generate as much power as we consume to reduce the amount of new power plants and grids that need to be built.

It is, he says, “a glimpse toward the future.” 

Marcie Geffner is an award-winning freelance reporter, book editor and blogger whose work has been published by a long list of financial, mortgage and banking websites, trade magazines and newspapers. You can find her on Google+.

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