The Local Government Climate and Energy Strategy Series provides a comprehensive, straightforward overview of greenhouse gas (GHG) emissions reduction strategies for local governments. Topics include energy efficiency, transportation, community planning and design, solid waste and materials management, and renewable energy. Households across the nation spend more than $160 billion on energy to heat, cool, light, and live in their homes each year, and residential energy consumption accounts for more than 20 percent of the nation’s total energy consumption (U.S. EPA, 2006b). These energy costs contribute to the overall financial burden of housing, and can make housing unaffordable for many families. In 2006, close to 40 million households spent 30 percent or more of their incomes on housing—the threshold used by the U.S. Department Housing and Urban Development (HUD) to identify affordability (see text box at right) (Brennan and Lipman, 2008). To help make housing more affordable, HUD and other public and private entities administer a number of assistance programs. For example, in 2008, HUD provided support to approximately 5 million low-income households through its public housing, rental assistance, and other housing assistance programs (U.S. HUD, 2008a).