Two architecture firms have been honored for their winning designs in the Carbon Challenge, a home-design competition that challenged participants to consider the environmental impact of building materials.

The competition, open to building designers nationwide, focused on two types of homes in two cities—a Habitat for Humanity house in Providence, R.I., and an urban row house in Baltimore. Using life-cycle assessment software from the Athena Sustainable Materials Institute, designers were able to determine the impact of the greenhouse gas emissions from the products in their designs. 

For Carbon Challenge Providence, entrants were tasked with designing a Habitat for Humanity house for a vacant lot in the city’s Olneyville neighborhood. ZeroEnergy Design’s winning entry is a wood-framed four-bedroom, two-bath home with a gabled roof suitable for the neighborhood’s traditional architecture. By combining an airtight, well-insulated building envelope, high-efficiency windows sited for optimal solar orientation, a 7.5-kW solar array, and a range of other features, the house is designed to use less than half the energy of a code-built home. Other features include rain barrels to collect water for landscaping, a two-track driveway to decrease impermeable surfacing, and an insulated basement. 

For Carbon Challenge Baltimore, entrants were tasked with updating Baltimore’s iconic row houses for a vacant block in the city’s Oliver neighborhood. The winning concept from Phillip Jones of Cho Benn Holback + Associates modernizes the traditional row house design with an open floor plan that maximizes daylight; a wide, semi-enclosed front stoop; and a roof deck with covered and uncovered entertaining areas, green roofing system, and solar hot water collectors. The design’s rammed-earth construction, a highly efficient building method that stores heat in the winter while blocking it in the summer, contributed significantly to its lower carbon footprint. 

As a joint campaign of the U.S. Forest Service Forest Products Lab and APA-The Engineered Wood Association, the Carbon Challenge seeks to educate home designers, builders, and communities about how sustainable design strategies can address the long-term environmental impact of a building and disaster resilience, as well as promoting the use of wood as a component to sustainable design. Cash prizes totaling $20,000 were awarded for designs based on their life-cycle assessment score and for designs demonstrating the best curb appeal, the most affordability and the best use of wood. Click here for a full list of winners.

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