2011年6月16日 星期四

Latest in energy efficiency: homes without furnaces

Everyone needs a home, but not every home, it seems, needs a furnace, even in Cleveland.

A house built for a new museum exhibit shows how walls more than a foot thick, big triple-pane windows, doors like bank vaults and clever engineering can cut heating and cooling costs — and pollution — by 90 percent.

The house keeps a comfortable temperature year-round. No need for heavy sweaters, no drafts, no noise.

Thousands of furnace-free homes in Germany have been built to this cutting-edge efficiency standard, but only 15 U.S. buildings are certified to the same level of extremely low energy use. Until now, none has been open to the public.Choose from one of the major categories of Bedding,

The people in Cleveland who made the exhibit happen are enthusiastic about the idea, known as a "passive house." It costs more than conventional housing, to be sure, as much as about 20 percent. The economics improve if the special equipment the house needs becomes locally available, and energy prices rise.

Meanwhile, the Cleveland Museum of Natural History decided to give its visitors a peek at this possible future. The house was intended as a can-do complement to a traveling exhibit on climate change that will open in July.

"We have to get beyond incremental improvements to get a dramatic breakthrough," said David Beach, the museum's director of environmentally sound urban practices. This house, he said, is "an example of a new way of living."

Special insulation

What makes the two-story house special is an insulation system with a sealed air barrier in the walls that makes it work like a thermos. A German-made ventilator transfers heat from the stale, outgoing air to the fresh air coming in, so little heat is lost.

Two ductless air-source heat pumps, which look like white rectangular boxes on the wall, one upstairs and one down,Not to be confused with RUBBER MATS available at your local hardware store supply all heating and cooling. They run on the energy equivalent of two hair dryers.

Because the house is insulated so well, it can hold heat from sunshine, body heat, lights and appliances.

Amory Lovins, author of an upcoming book about new ways to get and use energy, "Reinventing Fire," built a highly efficient house warmed mostly with these heat sources in Colorado in the early 1980s, an early inspiration for passive houses. The house is wrapped around what Lovins calls the jungle, a 900-square-foot indoor garden where bananas, mangos and other tropical fruit grows when temperatures outside are 30 below.

Wolfgang Feist, who founded the movement in Germany, visited and discussed the economics before he built his first house, Lovins said.

"He really nailed down how the thing worked, with very fine engineering," Lovins said.

In the Cleveland house, built to Feist's specifications, the living room has huge, south-facing windows. The first level has an open floor plan with a kitchen and dining area, as well as a mudroom in back and a slate entry in front.

Refinished oak floors salvaged from a torn-down house are used throughout. Furniture pieces are made of recycled materials, such as tables composed of wood from demolished houses. Cabinets,Save on hydraulic hose and fittings, fixtures and appliances are energy-efficient and locally made.

Upstairs, the master bedroom has large windows, much like the living room. The house has two other bedrooms and 2 ? bathrooms. Including the basement, it's 2,500 square feet.

The south-facing windows receive maximum solar heat in winter, when the sun is low in the sky. A ridge over the windows will block some sunlight in summer.

The house stands on the edge of a grassy circle, with big oak trees, that anchors a cultural center, including the Cleveland Museum of Art, an orchestra hall and a botanical garden. The house in October will be moved to a neighborhood a half-mile away and sold.

Cleveland endures cold, cloudy winters, a challenge for a passive house, because the colder and darker the winter, the more insulation is needed. It would be easier to build a passive house in Columbus,From standard Cable Ties to advanced wire tires, Ohio, or even Boston, which has the same cold but more sunshine, Beach said.

"If we can do it and achieve certification, you can do it anywhere," he said.

Certified passive

The person who does the certifying is Katrin Klingenberg, director of the Passive House Institute U.S. in Urbana, Ill. A certified passive house must meet the same energy-saving standards as in Germany. This "energy metric" meets the target of an 80 to 90 percent reduction of heat-trapping gases, the amount deemed necessary by midcentury to improve the odds of avoiding dangerous climate shifts.

It also makes economic sense, Klingenberg said. "It's a return on investment from day one."

The length of payback for the house depends on energy prices. According to the Department of Energy, it costs more than $900 a year to heat and cool an average house in the region.

Gene Troiano, treasurer of Perry Homes, an Ohio builder, said it cost roughly 6 percent more for his company to build a house qualified for the government's Energy Star rating. That's not as high-tech as the museum's model. The Environmental Protection Agency says Energy Star new homes are 15 percent more energy efficient than homes built to the code of 2004.

Perry builds only Energy Star homes. Troiano estimates the extra cost at $10,000.

"We try to explain it's a monthly savings, too, that you still come out positive," he said. But with the economy the way it is, "people are skeptical."

Look of the future

The people involved in the Cleveland house want to show what the future might look like.

Mark Hoberecht, who took a course from Klingenberg's institute, is its consultant for achieving passive-house certification. By day, he's a NASA engineer, managing fuel-cell development for space vehicles at Cleveland's Glenn Research Center.

"European governments have mandated energy-efficiency standards, so manufacturers produce the products," Hoberecht said. "If more were made here, the cost premium wouldn't be as great.Full color plastic card printing and manufacturing services."

The museum had the windows, doors and ventilation system shipped from Germany. The small heating-and-cooling system is from Japan. The imports added to the costs, as did the extra building requirements for a house that will be moved.

Architect Chuck Miller, who designed the house, said the 20 percent premium, which doesn't include the moving-related costs, stemmed from start-up obstacles.

"In time, that 20 percent premium will disappear," he predicted.

He said that when he renovated a building a decade ago, he paid about 20 percent more to use sustainable products such as formaldehyde-free wood. Now the products are mainstream and don't cost as much, he said.

Ellen Vaughan, policy director for high-performance green buildings at the Environmental and Energy Study Institute in Washington, says passive houses make sense.

"If you take the parts of the building that are going to last the longest and you make them the most energy efficient and durable, that's going to pay off in the long run," she said.

The long run could last a long time.

The Cleveland house was built in two months, but designed with great precision in a way that prevents water damage and is very low-maintenance, said Chris Kontur, the construction coordinator.

"This is a 500-year house."

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