This document discusses opportunities for reducing carbon emissions from residential buildings in the United States. It notes that residential buildings account for 21% of US CO2 emissions and emissions from residential buildings have increased substantially in recent decades. It also outlines opportunities to reduce emissions from multifamily housing, which accounts for 35 million US households, and single family homes, which account for approximately 75 million US households. Specific strategies discussed include energy efficiency upgrades, financing innovations, information programs, and targeting older housing stock.