D e s e r t E x p o s u r e
April
2009
Home, Green Home
Lizard Stone Builders pushes the envelope to create a zero-energy house in Silver City's historic district.
By David A. Fryxell Photos by Lisa D. Fryxell
To look at it, the dun-colored house at the corner of 10th and West streets in Silver City seems like nothing out of the ordinary — and that's the whole point.
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The "zero-energy" house
is designed not to stand out from its neighbors. |
You'd have to peer really closely, say, at the electric meter to notice that the dials are spinning backwards, selling power from the sun to PNM. Or you'd have to step inside on a chilly winter day and feel that it's a comfy 65 degrees in the house, but the heat's not on. And there's simply no way to tell that the house features locally purchased materials, from the basement to the MasterCraft roof, or that it's insulated not with prickly pink fiberglass but with the lint and leftovers from making blue jeans.
"Our greatest goal in a building like this was to make it normal," says Mark Austin. With partner Dan Clements, Austin owns Lizard Stone Builders, LLC, a Silver City builder of energy-efficient, solar homes. The house at 910 West St. — built on spec as a "zero-energy" dwelling — is designed to showcase just how "green" and energy-smart such a home can be without looking, well, weird.
"We wanted to blend into this historic neighborhood," Austin explains, opening the handcrafted door handle made, like all the house's metal fixtures, by local blacksmith Jim Pepperel. "People have been building 'earthships' for decades, and many of them are wonderful, but. . . ."
His voice trails off, but his point hangs in the air: Many earth-friendly houses simply don't look like homes. Or they require sacrifices and chores that ordinary homeowners might not be willing to make or perform. Austin says, "This house doesn't require anything extra of anybody."
Within those constraints of "normality," however, Austin and Clements set out to push the envelope. "People have a lot of different ideas about what makes a house 'green,'" Austin goes on. "We tried to get as much 'green' as possible into this house. The idea was to do everything right from the very beginning.
"A lot of people do 'green' building," he says, stepping into the slanting light beneath the living room's high, wood-beamed ceiling. "The problem that people struggle with, though, is that 'green building' is not a very reliable box. Sometimes 'green' is just a marketing term — like 'eco-jetskiing.'"
Dan Clements caught the green-building bug first. He teamed up with some fellow enthusiasts, but Clements proved to be more of a "go-getter" than the rest, says Austin, with whom Clements then partnered.
Austin had gotten "bitten" while living on a sailboat for several years. "It was so evident to me how wonderfully you can live with solar energy," Austin says, his halo of curly blond hair catching the sun streaming in through the front windows. "I had a VCR, microwave, a freezer and a great boat, and all of it was powered for free!"
Incorporating as Lizard Stone Builders, Clements and Austin started construction on their zero-energy house in the late fall of 2007. The roughly 2,100-square-foot, three-bedroom, three-bath house is finally almost finished and ready for sale ($419,000, if you're curious). In the meantime, Lizard Stone has also built a second zero-energy house, this one all on a single floor, for a customer.
Besides energy-efficiency, the builders wanted to make the West Street house as homegrown as possible — patronizing local eco-building firms such as Material Good and Gila Eco-Design, as well as Syzygy, the Silver City craft-tile maker. So, for instance, Material Good supplied the soy-based stain for all the wood surfaces plus the Yolo paint, made free of volatile organic compounds (VOCs). Gila Eco-Design was the source for the built-in shelves in the master bedroom, which came from a company that manages its own forests and uses draft horses instead of trucks and tractors.
Every element of the house had to meet a similarly tough ecological standard. All the wood floors and steps are covered with bamboo (also from Material Good), a renewable resource. The countertops (ditto) are fashioned from 100-percent recycled cashew-nut solids. Even the Ponderosa-pine vigas overhead, soaring across the living room, were locally harvested by Gila Woodnet ("Seeing the Forest for the Trees," March 2006), which specializes in logging timber that the Forest Service wants to get rid of.
The living-room floor, too, uses local clay — and lots of it. The thick, heat-absorbing floor is part of the passive-solar scheme that keeps the house warm. "This room is the real engine of the house," Austin says.
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Wherever possible, local materials
were used-including the vigas, the fireplace stone and even the clay
for the floor. |
The windows are arranged, he explains, to maximize the interior sunlight during the cold months. After the spring equinox, though, the sun no longer beams in.
"The sun warms things. We're not running any heat right now," says Austin, clad in shorts on a late-February afternoon. "I came in here in December when it was 23 degrees outside, and it was still 63 in the house — with the balcony door upstairs open. Purely passive solar."
Working in tandem with the clay floor to capture the sun's energy are the walls, built of 10-inch-thick autoclaved aerated concrete blocks (AAC). Developed by the Swiss in 1923, AAC blocks are actually more air than they are concrete, making them surprisingly lightweight compared to standard building materials; a four-by-two-by-two-foot block weighs about 50 pounds. A combination of concrete and recycled materials, filled with millions of tiny air pockets until the blocks are 80 percent air, creates insulated blocks that provide cost-effective thermal insulation (R value 28), resistance to fire, mold and pests. They provide acoustic insulation and simplify construction, Austin says.
Even the concrete component lives up to Lizard Stone's exacting earth-friendly standards. It contains recycled fly ash, a "scrubbed" byproduct of coal-burning power plants.
To finish the interior walls, the AAC blocks are covered by a two-inch-thick layer that accommodates cutouts for electrical outlets. There's not going to be any breeze coming in around those outlets, Austin notes.
Where standard construction might use nine layers to build a wall, Lizard Stone needs only five. "That reduces labor, cost and waste," he says. "And it means there's less Tyvek covering the world."
Just in case the passive solar captured by the walls and floor, plus the in-floor hydronic heating (he's getting to that), aren't up to a really cold winter day, the living room also has a Rumford fireplace. Two small sculpted coyote heads decorate either side of the fireplace. While the right coyote is just for decoration, the left critter has a purpose: Air draws in through a hole at its mouth, to be preheated before feeding the high-efficiency fireplace.
After a tour of the first-floor kitchen, bedroom and bathroom, Austin leads the way up the bamboo-covered steps to the second floor, which holds the master bedroom and bath. All the bathrooms, he points out, boast dual-flush toilets, which save thousands of gallons per year by better matching their flushing power to the need. The second zero-energy house they've built will further save water by using rainwater in the toilets. (Here, rainwater also gets collected, but only for outside watering use.)
The balcony off the master bedroom gives a view of the house's off-street parking, which features plug-ins where a future owner could juice up his hybrid cars. "You could fill your gas tank off the roof," Austin says with a smile.
That's because the house sports 16 photovoltaic solar panels, totaling 2.1 kilowatts of electricity-generating capacity. Actually, however, Austin's using poetic license with the notion of powering hybrid cars straight from the house: Lizard Stone has taken advantage of the house's in-town location, on the power grid, and avoided the need for bulky, expensive batteries to store solar-generated electricity. Instead, the house simply uses conventional power from the electric grid, while selling its own solar power to PNM at a premium retail rate. The difference between power purchased from PNM and power sold back to the utility, Austin figures, ought to net the homeowner $50 to $75 a month.
"There's a tremendous excess during the day," he says. "In effect, we're storing our power in the grid."
The balcony also overlooks the flat, rectangular panel of the passive-solar water heater. But to really understand how that works, Austin says, you have to go down to the walkout basement — clearly his favorite part of the house.
Downstairs, Austin gives a brief tour of what could be a third bedroom or a home office (especially since it has its own entrance), plus another bathroom. Then he leads the way into the utility room, home to not one but two hot-water tanks and a neat nest of black tubing and red-rimmed dials.
"I like this part a lot," Austin confesses.
Again, the notion of a solar water heater is a bit inaccurate, as what the sun striking the roof actually heats is ethylene glycol — the same substance used in antifreeze. That way, what gets pumped up to the roof for warming during cold weather doesn't freeze before the sun hits it. From the passive-solar panel, heated glycol circulates down to the first tank — really just used as a holding tank — where the heat gets exchanged from the glycol to water. The warmed water then flows to the second tank, a commercial-grade Polaris hot-water heater. When the sun is really shining, the Polaris doesn't have to work at all to get the water up to temperature.
From the second tank, that complex of tubes and dials sends hot water into a continuous loop throughout the floors, providing radiant heating. When you want to take a shower, the same system provides instant hot water — no waiting. In summer, the tubes in the flooring carry water straight from the city's underground pipes, cooling the slab instead of warming it.
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Mark Austin shows
off the hydronic radiant heating system. |
The combination of radiant heating — rather than forced-air heat from a furnace — and the passive-solar warming of the walls and floors enables the house to have that soaring ceiling in the living room. "Air is a great insulator, but it doesn't actually conduct heat very well," Austin explains. "The mass of the house is what's warm. That's why we don't care about high ceilings. We don't have to care about our air."
The utility room also houses the inverter that turns 360 DC power into 120 AC power for selling back to PNM. Austin shows it off like a proud papa.
Despite all the house's innovations, though, Lizard Stone has had to make some compromises. Stepping out the downstairs walkout, for example, you can see pressure-treated lumber. "There's OSB in the house," Austin allows, referring to "oriented-strand board," an engineered wood product manufactured with waterproof, heat-cured adhesives. "It's required by code. Wherever wood touches concrete, you have to use treated lumber.
"We've tried to do our best possible work and still have a house that can actually be created. So, yeah, there's a framed floor. Still," he pauses, tugs thoughtfully at a curling lock, "this is pretty damn green."
Someday, however, Austin and Clements hope that houses like the one on West Street won't seem all that unusual. The house has been a work-in-progress, an experiment, but the lessons learned should pay off in a greener future.
"We've tried to be open-minded," Austin says. "Our attitude has been, 'Let's try something different.' If there's a new product out there, we'll take a look. It's way too easy to just keep using the same old inefficient technologies."
He fingers the blacksmith-crafted handle of the back door. "Certainly, we're not getting rich doing this. We're doing it because we care. We think this should be normal. We hope that 10 or 20 years from now, none of this will be special."
For information on Lizard Stone Builders, call 538-1233 or 519-9947, email info@lizardstonebuilders.com, or visit www.lizardstonebuilders.com
David A. Fryxell is editor of Desert Exposure.