Beyond efficiency: Sufficiency unlocks deep decarbonization of U.S. residential sector

Residential decarbonization strategies in the United States have focused predominantly on energy efficiency measures such as heat pump adoption and building envelope upgrades, while sufficiency—avoiding unnecessary energy demand while ensuring well-being—remains largely unrepresented in quantitative national scenarios. Here, we assess the effects of structural sufficiency (i.e., moderating dwelling size and promoting compact, multi-family housing forms) and behavioral sufficiency (i.e., adopting more conservative, health-informed thermostat setpoints) alongside energy efficiency and electrification using an integrated modeling framework that captures U.S. housing stock turnover and hourly, climate-responsive building energy demand. Under business-as-usual housing trends, residential floorspace expands by 55% from 2020 to 2050, and final energy demand increases by 11%. Relative to this trajectory in 2050, efficiency improvements and structural sufficiency reduce demand by 18% and 31%, respectively. When combined, they can lower demand by 45%. Adopting sufficient comfort setpoints further reduces final energy demand by 31–33% across housing stock scenarios. Our findings highlight that structural and behavioral sufficiency represent substantial untapped mitigation opportunities and should complement efficiency-focused residential energy policies while maintaining household well-being in a warming climate.