Refrigerants used in building systems have historically been a significant source of greenhouse gas emissions. While eliminating chlorofluorocarbons (CFC’s) and moving towards refrigerants such as R-410a were steps in the right direction, there is still more work to be done. As we evaluate the full global warming potential (GWP) of a building’s life cycle, it is important to consider how different types of refrigerants can contribute to greenhouse gas emissions. This session will explore the GWP of different refrigerants used in common systems such as VRFs,  how to design refrigerant systems for optimal operation & maintenance to reduce leaks, what alternative refrigerants are being developed on the horizon, and the regulatory/engineering hurdles that need to be overcome to implement them.