The phase-down mandated by the AIM Act will lead to R-410A's replacement by other refrigerants beginning in 2022. Alternative refrigerants are available, including hydrofluoroolefins, hydrocarbons (such as propane R-290 and isobutane R-600A), and even carbon dioxide (R-744, GWP = 1). The alternative refrigerants have much lower GWP than R-410A.