Abstract:
Austin, Texas has established a “Climate Change Equity Plan” to enable the city to reduce its community carbon emissions by 50% by 2030 on the way to achieving net zero carbon emissions by 2040. How and where we build housing is the most scalable sector for impacting critical climate change mitigation in the southwestern U.S. In Austin, community scale CO2e/year emissions (GPC) come primarily from housing operational use (44%) and the associated personal transportation use of residents (40%). To reduce Austin’s current per capita GPC of 10.8 metric tons of CO2e/year by 50% before 2030, the city is updating its land-use zoning codes, building codes, energy codes and affordable housing programs to incentivize the reduction of Austin’s total existing home operational energy use by 25%, and for the construction of 80,000 new Zero Net Energy (ZNE) housing units within the city’s urban boundaries, in just the next six years. To achieve this number of housing units, incentive programs must appeal to cost-conscious middle-income and affordable housing consumers, who represent two-thirds of the market. This paper will document six University of Texas at Austin Solar Decathlon houses and multifamily apartments that demonstrate how modular prefabrication construction can reduce building costs by as much as $20/ft2 of floor aera and absorb the increased costs of $5/ft2 to achieve the energy conservation savings required in the new U.S. Department of Energy ZNE Ready home standard and $7/ft2 for a grid tied ZNE home photovoltaic power system. These projects demonstrate how building affordable ZNE housing using existing off-the-shelf technologies can mitigate climate change.
Bio:
Michael Garrison is Professor of Architecture at The University of Texas at Austin. He holds the Cass Gilbert Centennial Teaching Fellowship in Architecture and is active in the design and construction of sustainable buildings. He has served as the UT-Austin faculty advisor for the 2002, 2005, 2007, 2015 Solar Decathlon Build competitions and the 2019, 2022 and 2024 Solar Decathlon Design Challenge competitions sponsored by the U.S. Department of Energy. Professor Garrison's has published numerous papers on sustainable design and his research has received grants and awards from, the U.S. Environmental Protection Agency, U.S. Department of Energy, U.S. Department of Housing and Urban Development, U.S. Department of Interior, National Park Foundation, National Association of Home Builders, and the American Institute of Architects Committee on the Environment and Design. Professor Garrison is the author of four books: Passive Solar Homes for Texas (TENRAC 1982) Building Envelope, with Randall Stout (NCARB 2004) and Building Envelopes (NCARB 2018) and SOLEIL: A Zero Net Energy Middle Density Housing Typology (NREL Smart Press 2023). He is past chair of the Resource Management Commission for the City of Austin, past chair of the University of Texas at Austin Faculty Building Advisory Committee and a founding member of the Austin Downtown Commission. Professor Garrison is a member of the Scientific Advisory Committee for the Advanced Building Skins Conference in Bern, Switzerland and a board member of Community Renewal International in Washington D.C.