About one-third of the global energy demand and one-fourth of global greenhouse gas emissions come from the building sector. Global building energy demand can be reduced by one-third by 2050 if identified best practices in energy efficiency are implemented at a large scale across regions. The major barriers to creating efficient buildings are institutional and behavioral, rather than technical or financial. The BEA aims to break down these barriers by increasing global and cross-sector collaboration. The Building Energy Efficiency Accelerator (BEA) assists subnational governments in speeding up the adoption of best practice policies and the implementation of building efficiency projects. Its goal is to double the rate of energy efficiency improvements in the building sector by 2030. The BEA engages with cities through a menu of policy options and key actions, based on the needs of the city and the activities that the partnership can provide in each location. Cities will prioritize policies and activities, and the partnership will connect them to resources and engagement around those priorities.