A weak economy and rising energy prices have led to a buzz over building efficiency. Light bulb regulations, LEED and Energy Star ratings for homes and appliances, stricter construction codes, and government incentives are all parts of a national effort to cut energy waste in the building sector.
Nearly 40 percent of the nation's energy is consumed by homes and commercial buildings, which means that making them more efficient would not only save money but also drastically reduce carbon emissions. So a handful of builders are taking the idea one step further: Why construct a building that uses less energy when we can make one that uses no energy at all?
That's the philosophy behind "net-zero" buildings, and they have been springing up all over the country in recent years. By the purest definition, a net-zero building produces all the renewable energy it needs on site, drawing no more power from the grid than it gives back.
Considering that a shack in the woods is technically net zero, the concept isn't exactly new. But advances in technology over the past decade have made it easier to design sophisticated buildings that produce 100 percent of their own energy. At least 21 commercial buildings in the United States meet net-zero standards, according to a study released yesterday by the New Buildings Institute and the Zero Energy Commercial Building Consortium.
They run the gamut from offices to libraries to elementary schools. Researchers identified eight more unverified buildings that may also be net zero and an additional 39 that would classify if they installed more on-site renewable energy systems, plus dozens more under construction.
"We are seeing commercial examples of larger and more complicated buildings, which I think is a positive sign," says Stacey Hobart, the communications director at the New Buildings Institute. "Most of these buildings are smaller buildings, and most of them are early market adopters." Universities and local governments have also been responsible for much of the construction, largely because "they have a charge to say, 'This is a net-zero building,'" explains Hobart.
Expanding the possibilities
The first commercial-scale net-zero building was a center for environmental studies, completed at Oberlin College in Ohio in 2000. At that time, the project was largely an experiment in sustainable architecture.
"We intended to create not just a place for classes but rather a building that would help to redefine the relationship between humankind and the environment -- one that would expand our sense of ecological possibilities," said David Orr, the director of Oberlin's Environmental Studies program, at the center's groundbreaking ceremony in 1999. "We now know that such things are possible -- that buildings can be designed to give more than they take."
Commercial net-zero construction has steadily increased since then, with the number of completed buildings more than doubling since 2008, according to the latest study. Thanks to advances in structural insulation, energy-efficient appliances, new government incentives and the falling price of solar, expensive green-building projects -- like net zero -- are now within reach. And they don't always require a commercial-scale budget.
When Frank Walker first stepped inside a net-zero house in Denver two summers ago, he knew he wanted to trying building one himself. As the chief operating officer of a major Colorado homebuilding company, Oakwood Homes, he couldn't believe such a structure was possible.
"It was a 102-degree day in Denver, and the house was 72 degrees with no air conditioning and no cooling systems whatsoever," he remembers. "It's like building a Thermos."
The house was contracted by a local resident who had researched German "passive houses" and wanted to have one of his own. The design was so efficient, says Walker, that "you could heat the house using a hair dryer."