What should a commissioning provider know to undertake Building Enclosure Commissioning (BECx) with the goal to conserve energy, specifically achieving target energy consumption levels for LEED v4 and in-service energy-efficient performance? BECx activities important to producing a durable, resilient and successful building enclosure can also assist with saving energy and passing future energy audits. Topics, illustrated by a case study, will include: the OPR, critical building science and architectural issues to address in design review and specs, computer simulations, and performance testing. Learning Objectives: Be able to discuss with Owners how BECx can help to manage risks and save energy during the design and construction of the building enclosure and throughout the life of the building. Understand the tasks associated with the BECx process. Describe the tests specific to the energy saving assemblies of the building enclosure. Explain how the requirements of LEED v4 and related industry documents impact BECx.