Image Credit: U.S. Department of Energy The One Sky Homes entry is built on a foundation of insulated concrete forms with the crawl space further insulated with EPS foam and protected from moisture by a vapor barrier.
Image Credit: U.S. Department of Energy Advanced framing includes 2x6 exterior walls on 24-in. centers, two stud corners and open headers.
Image Credit: U.S. Department of Energy The insulated concrete forms sandwich a core of steel-reinforced concrete between two outer layers of rigid foam insulation.
Image Credit: U.S. Department of Energy In the production category, New Town Homes won top honors with this two-story design.
Image Credit: U.S. Department of Energy Double-stud exterior walls are insulated with blown-in fiberglass insulation. The design sharply reduces thermal bridging without the addition of an outer layer of insulation.
Image Credit: U.S. Department of Energy This 8-kW photovoltaic array will help lower the homeowners' utility bills to an estimated $5 per year, according to the Department of Energy.
Image Credit: U.S. Department of Energy The affordable category winner is this 1,055-square-foot house in Bellingham, Washington, built by TC Legend Homes for $144 per square foot.
Image Credit: U.S. Department of Energy The house is built from SIPs. Exterior walls are 6 inches thick and the roof panels are 10 inches thick. The house was oriented on the site for passive solar gain.
Image Credit: U.S. Department of Energy
The U.S. Department of Energy has selected 28 builders and construction professionals for Housing Innovation Awards, recognizing their roles in developing technologies and designs that significantly reduce energy consumption. The awards were announced at an Energy & Environmental Building Alliance conference in St. Louis on Sept. 23.
The department’s Office of Energy Efficiency & Renewable Energy said the awards went to builders in the Zero Energy Ready Home program. There were three categories of home construction: custom, production, and affordable. In addition, Palo Duro Homes of Alburquerque, New Mexico, was given the Zero Energy Ready Leadership Award, and Jerry Wade of Artisitic Homes won a lifetime achievement award.
The department also recognized four professionals participating in the Home Performance with Energy Star program.
Home in San Jose wins top honors in custom category
The grand winner in the custom home category was One Sky Homes of San Jose, California, whose high-performance entry includes both a photovoltaic array and a solar hot water system.
Exterior walls are framed with 2x6s on 24-inch centers and insulated with R-23 dense-packed cellulose plus another 1 inch of EPS rigid insulation over the sheathing. Walls are finished in traditional three-coat stucco. The crawl space foundation is made from insulated concrete forms, with the slab insulated further with EPS foam.
The roof is framed with raised-heel trusses and insulated with blown cellulose to R-51. Windows are triple-pane, argon-filled units with a U-factor of 0.2. A blower-door test measured airtightness at 0.57 air changes per hour at a pressure difference of 50 pascals (ach50), good enough to pass the very tough Passivhaus standard.
Designers specified windows with a low solar heat gain coefficient (0.29) on the east, west, and north walls, in part to minimize solar gain from intense afternoon sunlight. On south-facing walls, the SHGC is 0.49, allowing winter sun to help warm the house interior.
The grid-tied 6.4-kW PV system consists of 28 panels that together will produce an estimated 11,000 kWh of electricty per year, or 13% more than the house will need. The extra capacity is to be used to recharge the homeowner’s electric vehicle.
Other features include a gray-water recycling system which stores water from sinks and showers for seasonal irrigation, Energy Star appliances, and high-efficiency lighting.
It achieved a HERS rating of -1.
Denver company wins in production builder category
New Town Builders of Denver, Colorado, picked up top honors in the production building category with a two-story, 2,115-square-foot home with a HERS rating of -3.
The house complies with the company’s stated goal of converting its entire product line to zero-energy-ready construction by the end of next year, according to the Department of Energy’s project fact sheet. New Town produced its first DOE Zero Energy Ready House only last year, but has quickly adopted the standard.
Construction details include:
- Exterior walls: Double 2×4 construction using advanced framing techniques and insulated with 9 1/2 inches of blown-in fiberglass (R-40.7). New Town Builders frames all of its houses with lumber from trees killed by beetles.
- Roof: The vented attic is framed with raised-heel trusses and insulated with blown-in fiberglass to R-50.
- Foundation: The conditioned basement is insulated with R-19 interior insulation.
- Windows: Dual-pane vinyl windows have a U-value of 0.25 and a solar heat gain coefficient of 0.27.
- Domestic hot water: Tankless water heater.
- Heating: The high-efficiency system uses a ducted heat pump, supplemented by a gas furnace when temperatures drop below 5 degrees F.
The 8-kW PV system will help the homeowners keep their annual utility bills to about $5. (The bills would have totaled $1,414 without the PV system.) New Town Builders said the estimated added cost of the house over one built to the 2009 International Energy Conservation Code was $22,000 without the PV system and $35,000 with the PV.
Bellingham, Washington, house wins in affordable category
In the affordable category, a 1,055-square-foot two-story house built with structural insulated panels (SIPs) and an insulated concrete form foundation was the top winner. Ted Clifton Jr. of TC Legend Homes built the house for about $144 per square foot, not including the cost of the lot.
The house is powered by a 3.2-kW PV system which will help the homeowners lower their utility bills by $556 compared to a house built to the 2009 energy code. Total utility bills are estimated at $283 a year.
Clifton designed the house with a simple, open floor plan that includes a 630-square-foot footprint and a 400-square-foot loft. The house, oriented for maximum passive solar gain, is built on a concrete slab insulated with a layer of high-density EPS foam (R-20) plus one 16-inch course of insulated concrete forms at the perimeter. The slab was stained and sealed and is used as the finished floor.
SIPs used for exterior walls are 6 inches thick and rated at R-26. The 10-inch-thick roof SIPs are rated at R-42. The building also has low air leakage, measured with a blower door at 0.67 ach50.
Some of the other features include:
- Windows: Triple-pane vinyl with a U-factor of 0.2 and a solar heat gain coefficient of 0.45.
- Heating and cooling: A single ductless minisplit heat pump located on the first floor.
- Ventilation: A high-efficiency, 30 cubic-feet-per-minute fan in the bathroom that runs continuously. Supply air is routed through a 100-foot long, 6-inch-diameter earth tube buried 2 feet underground.
- Domestic hot water: Gas-fired tankless unit.
All of the fixed lights use LEDs, while movable lamps use compact fluorescents. Appliances include a high-efficiency water-dryer combo unit.
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