Greenbuilt Tour: Airtight design slashes home's energy needs
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Courtesy of Klaus Meyer
Photo: Klaus Meyer and Susanne Schindler’s Passive House off Old Santa Fe Trail was built based on a decade-old German method that aims to reduce energy use by 80 to 90 percent.
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'Passive House' based on German building methods is one of 20 solar-powered and energy-efficient residences on display
5/10/2008 - 5/10/08
The 2,500-foot house Klaus Meyer and Susanne Schindler built off Old Santa Fe Trail can be heated with a hair dryer and works like a Thermos.Well, almost.
Outside and in, the home simply looks like a lovely piece of architecture with a metal roof, tiled floors and stuccoed walls.
But most of the home is put together based on a decade-old, German-developed building method called the Passive House, which claims an 80 to 90 percent reduction in energy needs compared to a standard-built house.
Meyer, a native of Germany, had already poured his home's slab foundation by the time he learned about the Passive House design. Lacking a superinsulated slab, his house is only about 70 percent more efficient than the norm, according to Meyer, a contractor, and Joaquin Karcher, the architect.
So it might take two hair dryers to heat it.
The house is one of 20 in Santa Fe, Albuquerque and Taos featured on this year's GreenBuilt Tour New Mexico next Saturday and Sunday. Homes in Oshara Village and several other Santa Fe residences, including one trying for gold-level LEED green-building certification, are all part of this year's tour.
New green-building standards in New Mexico, Santa Fe and Albuquerque, rising energy costs and tax credits for energy efficient and solar buildings, are helping move green building forward.
It would be easy to chalk the Meyer house up to another custom home far outside the realm of the average Santa Fean. But the Passive House principles used in the Meyer home can be applied to a building of any size using simple materials and at a cost easily recouped by the energy savings, the men claim. With heating-fuel prices increasing an average of 20 percent a year, it makes sense to build homes that need little or no heating, Karcher said.
The Passive House is designed for passive solar gain, but that comes second, said Karcher, who has a master's degree in architecture and owns One Earth Design in Taos.
A Passive House is designed first to be airtight and requires no conventional heating system. Walls, doors and windows are superinsulated. A controlled ventilation system brings fresh air inside without losing heat in the cold months.
Then the house is situated to take advantage of solar gain. "Before we look at passive solar, we look at reducing energy use," Karcher said.
The key is in how all the parts are put together, Karcher said. Every spot where a building material meets air or soil is a place where cold air gets pulled into a house. Every joint and every surface has to be airtight.
The superinsulation is what makes the house act like a Thermos, holding heat in.
In warm summers, the superinsulation acts to keep the house cool.
Meyer's exterior walls are insulated with shredded newspaper blown inside a double wood stud wall frame. "The blown-in insulation fills every gap," he said.
The windows have triple panes. Even the doors and door frames are insulated. "Without that, windows and doors are holes in the building envelope, like Swiss cheese," Karcher said.
Aside from the solar gain from south-facing windows and a clerestory, the only source of heat is provided by a wood-burning stove.
An automated ventilation system controls the flow of outdoor fresh air while recapturing 80 percent of the heat normally lost. All indoor air is replaced eight times a day. "Not having a ventilation system in an airtight home would be criminal," Karcher said. "You would get sick."
In Germany, architects and builders focused on using any material possible to make the buildings airtight and superinsulated. Karcher and others in New Mexico are using traditional materials like adobe, and recycled materials like newspaper, to create Passive Houses.
Meyer's house qualifies for a $20,000 state tax credit for its green design. He'll use that money to buy a photovoltaic system that will provide the home's electricity.
The first Passive House buildings were built in Darmstadt, Germany, in 1990 and since then, thousands more have been constructed in Europe. In 1996, the Passive House Institute was founded in Darmstadt to control the standard that all new homes built in Germany must meet by 2015, Karcher said.
Karcher said the Passive House design lends itself especially to multifamily homes — duplexes, apartment buildings and row houses. Karcher's company is developing a model duplex now with two 950-square-foot homes using all the same airtight, superinsulated principles. "These are geared toward mass production," Karcher said.
To find out more about the Passive House and see some of Karcher's plans, visit www.oneearthdesign.com.
Contact Staci Matlock at 470-9843 or smatlock@sfnewmexican.com.
IF YOU GO
What: GreenBuilt Tour New Mexico, a tour of sustainable homes and businesses in Albuquerque, Santa Fe and Taos
When: 10 a.m. to 4 p.m. next Saturday and Sunday
Cost: Tickets are $10 for adults and teens, $5 for seniors and children 12 and under. Tickets are available from La Montañita Co-op, Whole Foods, BioShield, Big Jo True Value Hardware and the Permaculture Credit Union.
Information: www.greenbuilttour.net