AIA Housing Awards: Single-Family
The upper half of the three-bedroom, 1,900-square-foot (177-square-meter) home is clad primarily in a concrete-panel rain-screen facade suspended between horizontal steel channels that wrap the top and bottom edges of the rectangular upper story. Outdoor deck spaces occupy the northeast and southwest corners of the second floor.
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A row of thin aluminum rods suspended between the steel channels gives a sense of definition to the deck spaces while still preserving the views. At the rear of the building, a narrow, wood-clad volume rises above roof level and cantilevers like a periscope beyond the eastern facade; inside, the home's only staircase culminates in a whimsical observatory overlooking the lake.
The dwelling received a Platinum certification under LEED for Homes, and earned a Home Energy Rating System (HERS) score of 33, meaning the house is estimated to use 67 percent less energy than a home built to the 2006 International Energy Conservation Code (IECC). A key contributor to the OS House's energy efficiency is its envelope, which uses Energy Star-rated windows and closed-cell foam insulation to achieve a minimum wall insulation value of R-35.
Other "green" features include a 4.2-kilowatt rooftop photovoltaic array, a solar hot-water array, a geothermal well system for heating and cooling, and a rainwater management strategy that includes both harvesting and diversion into rain gardens. The compact home's efficient footprint and extensive glazing also support natural ventilation and daylighting.
Since before the first Case Study Houses were built in 1945, architects of all kinds have tried to apply the 20th-century principles of mass-production and modularity to residential design in an effort to bring attractive, affordable, architect-designed housing to the masses. In its 2011 "production housing" category, the AIA recognized two such homes — both very green — intended to compete with more-conventional suburban speculative-housing offerings.
The 100K Houses are a series of compact two-story townhouses designed by Interface Studio Architects LLC to provide affordable, energy-efficient urban alternatives to suburban and exurban speculative homes. Eight such dwellings were built on three infill lots in the East Kensington neighborhood of Philadelphia, Pennsylvania, from 2008 to 2010.
The moniker for this line of roughly 1,000-square-foot (93-square-meter) homes reflects the target cost for construction — $100,000, or $100 per square foot ($1,080 per square meter), not counting the cost of land and "soft costs" such as architects' fees.
According to the architects, even within the constraints of this modest budget, the 100K Houses are designed to earn HERS scores between 42 and 24, depending on the house model. The first two-dwelling development has achieved a LEED for Homes Platinum rating, and a later project is targeting Passive House certification.
For anyone familiar with the stringent energy performance requirements of the Passive House certification standard, these minimalist townhouses — essentially flat-roofed, two-story boxes — will be intuitively familiar. This conservative approach to building design minimizes both construction costs and heat loss.
The 100K House designs emphasize highly efficient building envelopes constructed using either a double-stud framed wall system or structural insulating panels (SIPs), with a small total window area compared to the overall exterior surface area. Interior finishes include plywood, oriented-strand board (OSB), exposed concrete, and bamboo flooring. The primary exterior finish material is a painted or silkscreened fiber-cement board in a rain-screen system.
Other sustainable design features include rooftop hot-water and photovoltaic arrays, energy-recovery ventilators (ERVs), and radiant-slab heating systems.
Syracuse Passive House Prototype
The other production-housing honoree is the R-House, a two-story prototype home designed to take advantage of infill opportunities in the Westside neighborhood of Syracuse, New York. The basic model is a modest two-bedroom, two-bathroom, 1,100-square-foot (100-square-meter) house with a partial second floor and a vaulted living space. Third and fourth bedrooms can be added by fully enclosing the second floor, and another configuration option includes a rental unit.
Designed by Della Valle Bernheimer and Architecture Research Office, the angular R-House is clad in a corrugated aluminum siding. An unusual roof is pitched in two directions from a sloping ridgeline that runs between diagonal corners of the home's rectangular plan.
With no overhangs or gutters, the relatively seamless transition between wall and roof combines with sharp angles and reflective siding to express a simple crystalline form. At the front and rear are triangular corner porches.
Designed to meet Passive House certification standards, the R-House has thick exterior walls built from balloon-framed wall panels that use 16-inch (41-centimeter) composite wood I-joists as studs. Glazing is minimized and is concentrated in the front and rear walls to frame views.
The architects strategically used modest skylights and small windows in the side walls to admit daylight into central areas. The primary heat source is a solar-heated water-to-air system that uses a ducted heat exchanger tied into an energy-recovery ventilator.
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