This workshop will outline best practice steps and approaches to comprehensively enhance the energy performance of existing buildings to ZNE. The workshop will investigate retrofit opportunities in individual buildings as well as how advanced benchmarking can help prioritize opportunities across a portfolio. We will review technologies, approaches, processes as well as portfolio project prioritization methods. Case studies of building strategies and technologies will be presented including advanced strategies a design team can take to achieve ZNE on an existing building. The training will address operation and maintenance considerations, including energy monitoring for ongoing building performance