Energy efficiency soars to new heights in passive houses.
Highly efficient doors and windows are part of what keeps this “passive house” from losing heat. The house, on display at Ohio’s Cleveland Museum of Natural History, shows how walls more than a foot thick, triple-pane windows and clever engineering can cut heating and cooling costs — and pollution — by 90 percent.
CLEVELAND -- 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 in the U.S. there are only 15 buildings certified to the same level of extremely low energy use. Until now, none has been open to the public.
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 does, to be sure, as much as about 20 percent. If the special equipment the house needs becomes locally available, and energy prices rise, the economics improve.
In the meantime, 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 here 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."
Like a thermos
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 very little heat is lost. Two ductless air-source heat pumps, which look like white rectangular boxes on the wall, one upstairs and one down, supply all the heating and cooling needed. They run on the energy equivalent of two hair dryers.
Because the house is so well insulated, it can hold heat from sunshine, body heat, lights and appliances.
Amory Lovins, the 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. It's 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, came to visit 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.
The Cleveland house, built to Feist's specifications, has huge south-facing windows in the living room and an open floor plan on the first level.
Large windows, salvaged floors
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, 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 1/2 bathrooms. Including the basement, it's 2,500 square feet.
The big south-facing windows get maximum solar heat in winter, when the sun is low in the sky. A ridge over the windows will block some of the sunlight in summer, when the sun is high.
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. In October, the house will be moved to a neighborhood a half-mile away and sold.
Cleveland's winters are cold and cloudy, a challenge for a passive house, because the colder and darker the winter, the more insulation is needed.
"If we can do it and achieve certification, you can do it anywhere," he said.
The person who does the certifying is Katrin Klingenberg, the 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 home's payback time depends on energy prices. According to the Department of Energy, it costs more than $900 per year to heat and cool an average house in the region now.
Architect Chuck Miller, who designed the house, said "In time, that 20 percent premium will disappear."
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.
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."