California’s building sector accounts for approximately 25% of statewide greenhouse gas emissions, when accounting for fossil fuels consumed onsite, electricity demand, and refrigerants used in air conditioning systems and refrigerators. 12 percent of total statewide GHG emissions are emitted onsite in residential and nonresidential buildings, with natural gas combustion producing significant quantities of air pollutants such as nitrogen oxides (NOx) and carbon dioxide that contribute to poor ambient and indoor air quality and climate change. Electrification is a viable strategy for achieving significant and immediate reductions in greenhouse gas and criteria pollutant emissions from the building sector. This research addresses critical knowledge gaps regarding the status of electrification progress in commercial and residential buildings statewide, data gaps preventing accurate cost and impact estimates, populations under-served by existing policies, and the values and barriers affecting electrification decisions, providing the California Air Resources Board (CARB) with evidence-based findings to align policies and programs with the state's decarbonization and air quality goals.