Many organizations have set net zero goals for decarbonization of their existing building portfolios, but few have developed building-specific Strategic Decarbonization Plans to map out how to get there. Even fewer have embarked on implementation of such plans. This session will report on decarbonization planning and beginning implementation of the plans for two iconic commercial office buildings in San Francisco: One Maritime Plaza and 150 California Street. Panelists will share their perspectives as property manager, decarbonization consultant and mechanical design engineer, from initial charette through the conceptual phase, alternative strategy evaluation, design development and then initial implementation. The session will compare the different approaches taken based on each building’s unique conditions, including building envelope and glazing improvements, HVAC system reconception, electrical upgrades and potential for district heating. Panelists will discuss the technical and financial challenges that were confronted and how both buildings successfully progressed from planning to action.