Today, HFCs are the most commonly used refrigerants in new refrigeration and air-conditioning systems in the United States and increasingly in developing countries, but these refrigerants are potent greenhouse gases (GHGs) with global warming potentials (GWPs) ranging from hundreds to thousands of times higher than CO2. HFCs have been commercialized to replace ozone depleting chlorofluorocarbon (CFC) and hydrochlorofluorocarbon (HCFC) refrigerants, which have been or currently are being phased-out under the Montreal Protocol on Substances that Deplete the Ozone Layer. Reducing production and consumption of HFCs is the largest, fastest, and most cost-effective short-term climate mitigation option currently available and will have a significant effect by 2050. As the case studies in this report demonstrate, there are numerous cost-effective, safe, and energy-efficient climate-friendly refrigeration and air-conditioning technologies globally available.