steps aheadSnug construction and careful energy management help break new ground at this Innovative Green Home award winner.
This “Passive House” utilizes nontoxic and natural building materials including clay plaster, which helps balance indoor humidity levels while absorbing electromagnetic radiation and airborne toxins.
The home was designed with the entry leading to a foyer above a set of stairs that connect to the living room.
Despite the challenging lot, the home sits on a compact footprint with stylistic elements fitting its Santa Fe hillside setting.
Near an African mask, a planter of wheat grass rests on a half wall above the stairs.
The kitchen and living room share a purple adobe wall that provides thermal mass for absorbing solar energy. All of the home’s appliances are Energy Star rated for energy efficiency.
In one of the bedrooms, a cat lounges on a colorful spread.
This article first appeared in Winter 09 Su Casa
Klaus Meyer was committed to green, healthy building and had established his own construction company, EcoHouse Santa Fe, when he happened to see a German children’s educational TV show that inspired him to pursue a whole new level of energy efficiency in the homes he builds. Now Meyer’s goal for his own Santa Fe home, after he adds active solar systems for hot water and photovoltaic, is a zero carbon footprint: a house that creates no greenhouse gases—ever—as it meets his family’s total needs for electricity, cooking, and heat. This house recently received Su Casa and Build Green New Mexico’s Innovative Green Home award in our 2009 Green Home of the Year competition (see our Winter 2009 story "Better all the time" for more about the winners).
In 2005, the German-born Santa Fe resident was watching a German TV show via satellite one Sunday with his wife, Susanne Schindler, and their two children, when the show’s main character, a cartoon mouse, introduced the idea of the Passive House. Developed by Dr. Wolfgang Feist and other engineers at the Passivhaus Institut in Darmstadt, Germany, the Passive House is a popular concept in that country and is just beginning to be known in the United States.
Using a tiny model house, the mouse explained that if you make a building airtight enough, it will take very, very little energy to heat. But, of course, you need to breathe fresh air. The mouse explained that the Passive House is not only very airtight and easy to heat, but fresh air is also brought in continuously from outside through a special air exchange system. This system makes sure the home’s warmth is not lost when the air leaves the house.
Meyer was intrigued. Before that moment he had been only vaguely aware of the Passive House concept—as distinguished from a passive solar house, though both use passive solar gain for heating. The goal of a Passive House, and the origin of its name, is to create a structure so well insulated and airtight that it doesn’t need a conventional, or active, heating system at all. It basically heats itself.
Meyer’s previous involvement with green building in Germany included collaborating with an architect and constructing a five-story structure with a building-wide rainwater catchment system. When he learned about the Passive House, he was planning to build a home for his family in the foothills near Santa Fe. Meyer returned to Germany and spent some time at the Passivhaus Institut, learning all he could. “I had already decided to go into healthy building,” he says. “Then I saw this program, and now I had to have healthy and energy efficient.” What he ended up with is a home that is also eminently comfortable, inviting, and aesthetically pleasing.
Meyer worked with architectural designer Andreas Frick (now in Los Angeles) to design his home and began building in 2006. At about the time the home was being roughed in, he met Joaquin Karcher, a fellow German, an architectural designer, and the owner of One Earth Design in Taos. Karcher is heavily involved in Passive House design and building. He uses specialized computer software developed by the Passivhaus Institut, and which he adapted for the Southwestern American climate, to calculate how much energy savings Meyer could expect, given factors such as solar gain and a super-insulated thermal envelope. “I was already doing a lot right, but Joaquin helped refine it to the best possible Passive House with the design that I had,” Meyer relates.
As a result, the 2,500-square-foot, three-bedroom home requires as little as 20 percent of the energy needed to heat an average house. Karcher explains that according to the Passivhaus Institut (and Passive House Institute U.S.) standard, energy savings can reach as high as 90 percent—or to put it another way, the ideal Passive House requires as little energy to heat as the electricity it takes to run a hair dryer. He notes that to meet this standard, Meyer’s home would need more extensive passive solar gain.
Minimizing the home’s heat loss means, first off, maximum insulation and air tightness. Double frame exterior walls containing more than 13 inches of blown-in cellulose insulation from recycled newspaper provide the super-envelope encasing the house. The resulting insulation value is R-50 in the walls and R-70 in the ceiling, with triple-pane windows all around. “The most important thing is to spend the money on the envelope,” Meyer stresses. “You could save a couple thousand dollars on the envelope and put more into active solar, but that’s not the philosophy of this kind of house.”
The home’s virtual airtight seal is also achieved with the help of such elements as thermal bypass boxes around all electrical outlets and silicone sealing around wiring in and out of the boxes. “We don’t leave it up to the builder as to how tight he can build the home,” Karcher observes. “A lot of diligence to details is required for that. I think in Klaus’ house the indoor air climate is unsurpassed. It’s extremely comfortable.”
Meyer adds that the prevention of even small air leaks creates a more even temperature throughout the house, which means even greater comfort. The family moved into the home in the late fall of 2007. Heat during the first winter was provided by passive solar and a woodstove, with pipes under the floor bringing outdoor air into the stove, creating a closed system to minimize heat loss. Meyer plans to add an active solar system for hot water for both domestic use and radiant floor heat, eliminating the need for burning wood.
To make such an airtight house livable, engineers at the Passivhaus Institut came up with a mechanical system that replaces the entire volume of air in the house up to nine times each day. The fresh air is filtered to eliminate allergens and dust and is delivered by ducting throughout the house. The old air is drawn out through vents near the ceiling in the warmest rooms, including the kitchen and baths.
But before the old air is sent outside, as much as 95 percent of its warmth is transferred to the fresh air coming in by way of a heat exchange system inside a heat recovery box. The incoming and outgoing air doesn’t mix; rather, heat is transferred through the walls of the ducting, which intertwine within the box, Meyer explains.
“We moved in at Thanksgiving and there was a lot of snow, and no one opened a window for four months,” he relates. “Before, I could never sleep without an open window. This is the first house where I could do it.”
The Passive House works best with compact homes, rather than rambling houses with multiple wings, Karcher explains. More walls and non-south-facing windows means more heat loss. This sometimes translates into boxlike structures in Passive House design. Meyer’s home, on the other hand, combines a compact footprint with aesthetic and architectural elements appropriate for its Southwestern setting and hillside building site.
The house follows principles of Bau-biologie, such as using building materials with low embodied energy that are locally harvested, natural, recycled, and healthy. First introduced in Germany, Bau-biologie dictates design criteria to make a building healthier for people and the planet, including factors like passive heating and minimizing lot disturbance.
After reducing his home’s energy needs by 70 to 80 percent, Meyer plans to take care of the remaining 20 to 30 percent by means of the sun. Installing an active solar water heating system will yield state and federal tax credits. Meyer intends to use this money to purchase photovoltaic panels to provide electricity for the house. The photovoltaics will be tied into the utility company’s meter, with extra power sold back to the company. “Our goal is zero cost for energy,” he says.
Meyer and his family are not new to using the sun for electricity. In 1995, the family left Germany and spent more than four years on the road in India and Africa, living in a small RV Meyer custom-outfitted with photovoltaic panels on the roof. In 1999, when their 12-year-old son appealed for settling down so he could have friends and a dog, the family decided to make Santa Fe their home. In 2004, they spent six more months on the road, this time in South America, before returning to Santa Fe.
“Sometimes you just have to leave the system,” Meyer says of their traveling days. Smiling, he adds, “Now we have no time for traveling; we have to save the world and bring the carbon footprint down.” That applies not only to his family’s home. He and Karcher have teamed up, with Karcher as architectural designer and Meyer as builder, on Passive House projects and other green and healthy homes. Currently in its beginning stages, the venture will engage Meyer’s passionate commitment to a more sustainable future.
“You know, about 48 percent of carbon dioxide [in the atmosphere] is from energy used by buildings,” he points out. “Now people are waking up and saying, ‘hey, let’s think.’ When you build a house, it runs for the next 50 years. So if you want to save energy, you have to do it now.”
Gussie Fauntleroy, a longtime Santa Fe resident, writes on homes, art, and architecture for national and regional magazines, among them Art & Antiques, Southwest Art, New Mexico Magazine, and Native Peoples Magazine. She is the author of three books on visual artists.