Interesting Energy Articles
Grand Award
BrightBuilt Barn ..... By:Rick Schwolsky
Small is not only beautiful these days, but also more practical,
adaptable, and sustainable, as exemplified in the 640-square-foot
BrightBuilt Barn prototype production house. Every aspect of this
LEED-Platinum home, from materials selection to net-energy performance
to water efficiency, was thoughtfully integrated into its design and
carefully executed in its pre-fabricated construction.
The judges commended BrightBuilt’s simplicity of form and how well it
“lives” for its size due to its flexible open plan. But they also
appreciated the performance-focused features integrated into a
replicable package, and the obvious results, including a HERS rating of
23 and an ACH@50 of 0.590. “From its inception, the design was driven by
five guiding principles: livability, sustainability, replicability,
disentanglement, and education,” explains Robin Tannenbaum of project
designers Kaplan Thompson Architects.
The prototype is packed with every option available now in the for-sale
models that Kaplan Thompson and Bensonwood Homes are offering: a
super-insulated shell (R-40), a 6.2-kW grid-connected PV array and an
evacuated-tube solar thermal system, a supplemental heat pump and heat
recovery ventilation, high-efficiency lighting fixtures, and
water-efficient plumbing fixtures. A way-cool real-time energy
monitoring system includes an LED light skirt on the exterior perimeter
that glows green when the house is a net-producer and red when it’s
using grid power.
Production models are fitted for options, shop-fabricated, and shipped
to the site for fast, efficient assembly. “This house pulls everything
together,” said one judge. “You don’t have to say it’s a good green
house, it’s just a good house.”
When the power went out for hours during Virginia’s massive snowstorms last winter, architects Chris Hays and Allison Ewing didn’t worry too much about the frigid temperatures outside. They were enjoying the southern sunlight pouring through their home’s two-story windows, while the fiber-cement floors soaked up the heat and the SIPs walls and roof wrapped them like a warm blanket. More than a decade after building their own home—an experiment in sustainable, affordable design—the Charlottesville couple experienced in a new way the power of passive solar. As former partners at William McDonough + Partners in Charlottesville, known for its pioneering environmental designs, Ewing and Hays were at the forefront of the modern green building revolution. And although the movement hadn’t yet hit its stride when they completed this house in 1999, their approach was so sound it still forms the basis of their work today. Passive solar design features that help heat the home in the winter and keep it cool in the summer are defining strategies, along with a thermally efficient building envelope, material reuse, a focus on indoor air quality, and stormwater mitigation. “Our home would probably be LEED-certified today,” Ewing says. “If we upgraded our HVAC equipment, we’d easily make Silver or even Gold, based on what we’ve been seeing on other projects.” They’d found their ideal lot—in the established Woolen Mills neighborhood near downtown—and with views that face south. Like a good neighbor, the house aligns with the street grid, which placed it on a roughly east-west axis, allowing the most abundant sunlight to flood the living spaces in back. The building is separated on the ground level—work studio on one side of a cypress entry deck, living spaces on the other. Upstairs, an enclosed bridge connects the master bedroom above the studio with the children’s bedrooms. The floor plan captures the site’s solar energy by banking all the utility areas—kitchen, three baths, and equipment closets—on the street-facing north side so that the two-story living areas can enjoy the southern exposure. To achieve that tricky balance between natural light and unwanted heat gain in a warm climate, the pair worked with a daylighting consultant and combined 0.36-SHGC double-pane windows with a series of louvered cypress panels that cover the upper part of the large windows. “Because the back of the house has some western exposure, the deep overhangs weren’t enough, so the louvers and a trellis shading the first level were critical,” Ewing explains. “We didn’t feel it was appropriate to rotate the house true south, because that would have put it at odds with the urban environment.” Hindsight is 20-20, but their original vision was crystal clear, too. Designed on an 8-foot grid to utilize standard-issue building materials, the house’s low-maintenance efficiencies have proven their staying power. The fiber-cement exterior siding has needed no paint touch-ups in the years since they installed it, and the durable fiber-cement floors store and release heat from the winter sun, as the couple had hoped. Custom windows that go up to the ceiling turned out to be a smart splurge, too, since the high operable windows in the living room and on the second-floor bridge exhaust warm air from below. For mechanical systems, they chose “state of the shelf” technology—tested products that were becoming mainstream. In addition to a Trane variable-speed, high-efficiency two-stage gas furnace with two zones, they installed a Trane VAV (variable air volume) handler, which provides fresh air cued by carbon dioxide sensors. But while their 12-SEER cooling unit was the gold standard a decade ago, they now spec 18- or 19-SEER products. Indeed, technology, and its costs, has evolved over the last 11 years. If the couple were designing their home today, they say they would incorporate solar thermal and tankless hot water. The crawlspace would be conditioned, too. “The current thinking is to seal the crawlspace and pass some air through to create warmer floors and a thermal buffer below the house,” Hays says. Likewise, the cypress deck outside will soon be replaced with Cambia, a lower-maintenance poplar that’s been treated with heat instead of chemicals to resist rot. The architects like it because it looks like ipe and doesn’t have to be stained. “You can’t get certified ipe anymore, which is a signal that it’s been over-harvested,” Ewing says. Green checklist notwithstanding, she and Hays are quick to point out that the highest goal of a sustainable house isn’t just environmental virtue, but also that the landscape and building have a lively relationship. “The pervasive light and the sense of connection you feel to the outdoors as you move around the house is more than a technical goal; it becomes a spiritual thing,” says Hays. “Every time we’ve been away, we’ve felt how lucky we are to come back to this place to live.”
Case Study: North Carolina Remodel Soars Beyond LEED Platinum
Solar panels, geothermal, water collection, and a green roof top a
lengthy list of sustainable features in this team-designed LEED-Platinum
renovation.
After his parents moved into a retirement community, Jay DeChesere, AIA
nearly sold their Wilmington, N.C., home of 20 years. Instead, he opted
to transform the shed-roof house into a living laboratory for green
building, and in doing so recorded 113.5 points in the LEED for Homes
program, one of the highest ever achieved by a remodel.
The gut rehab expanded the 1,230-square-foot ’80s-era structure to 1,648
square feet, largely by converting the garage into living space and then
adding a carport. To make the home a true demonstration project,
DeChesere approached vendors for discounts and formed a design team to
pre-plan various scenarios and determine the most sustainable options.
The charrettes included an eco broker from Suntrust bank who provided
advice on how certain decisions might impact the opinions of buyers and
the dwelling’s resale value, including how to help outsiders understand
the purpose of the property’s limited turf area, whether a green roof
would be well-received, how to best orient the new open floorplan, and
what was the most marketable number of bedrooms for the size (three).
A key concern of the broker, for instance, was that the
garage-turned-home-office in no way resemble its former self. One area
where the team ignored resale rules was converting the fireplace into a
skylight shaft with an entertainment center below. The risk paid off, as
DeChesere says it’s been one of visitors’ most talked-about features.
Once overall design decisions were made, the team went all out, jumping
at every opportunity to make sustainable selections, including a 3-kW
14-panel solar array (ground-mounted in the backyard because the
existing roof did not offer optimal positioning). Excess power is sold
at one-and-a-half times cost to NC GreenPower, a non-profit that uses
the energy to supplement the state’s existing power supply; power is
also sold to local utility, Progress Energy. Selling the excess
kilowatts eliminated the need for storage, DeChesere says, and should
help pay the PV system off in six years.
“The whole issue was to make it a demonstration project to show to the
public all the strategies available,” explains the architect, who says
the team viewed it like taking a dinner menu and sampling each dish.
With that in mind, the house also includes a geothermal system, solar
water heating, a green roof, and water reuse for toilet flushing.
But it wasn’t all about flashy products—greening the home started with
evaluating the existing envelope. After the crew stripped the house down
to the studs, they found that the original builder had used, in addition
to fiberglass batts, a 3/4-inch foam insulation board with a vinyl vapor
barrier on the outside of the wood studs, creating a thermal break that
reduced or eliminated heat/cold transfer through the studs and also
provided a natural air seal and some additional R-value. When compared
to a foamed-in-place insulation, the wall was almost comparable and with
the additional cost considered, it made more sense to leave the batt
insulation in place.
The attic's existing blown-in insulation had settled to R-5. The Energy
Rater modeled the home with an R-30 blown-in attic insulation and a
radiant barrier versus a foamed-in-place insulation at the roof and
found that there was very little difference in the required HVAC system,
so little that the additional cost of foam, again, did not make sense.
The remodeled house achieved a HERS rating of 28. Per a blower-door
test, the final leakage ratio was 0.21; the final leakage ratio for the
duct-blaster test was 0.23.
The crew diverted 91% of waste, including reusing wood studs, donating
and recycling materials, and diverting drywall and wood scraps into lawn
supplement or mulch. The design team had planned to keep the
five-year-old insulated vinyl siding, but when some of the material got
stripped off during construction, the remaining panels were sold on
Craigslist and replaced with pre-painted fiber-cement from James Hardie.
Among the home’s other conservation-minded features:
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Occupancy sensors
*
LED and CFL lighting
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Energy Star-rated fiberglass Pella windows with Low-E4 glass
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Energy Star-rated Whirlpool appliances
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85% of rain falling on the roof is collected for irrigation and toilet
flushing
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Zone-controlled and rain-delay-controlled irrigation
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American Standard low-flow showerheads and lav faucets
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Toto 1.28-gpf toilet; American Standard dual-flush toilet
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Icestone recycled-content bathroom countertops
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Reuse of all studs from demolition
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Locally harvested and manufactured wood products; FSC-certified lumber
where appropriate
* Concrete driveway reused as sidewalk pavers
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Fresh-air system
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MERV-13 filters
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Low- and no-VOC finishes
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Non-toxic pest control
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Concrete countertops made with 40% recycled content
Though he admits the house features more elements than some clients are
willing to pay for (after all, the goal was to experience and showcase
as many sustainable features as was practical), DeChesere sees
opportunity in showcasing the possibilities and appreciates the lessons
that owning the decked-out dwelling provide him as an architect.
“This whole thing is a demonstration in the fact that we can live here
and make recommendations for the client,” he says. Experiencing the
products first hand helps him spot durability issues for new materials
or learn nuances of technologies like the solar hot water system, advice
he can pass along to future clients installing the systems.
As part of the demonstration goal, the home was (and continues to be)
featured on solar and green-home tours, a tactic that is helping
generate new business, DeChesere says. “People are pretty quick to
understand and be impressed.”
