About HFCs
HFC refers to the chemical composition of the refrigerant. HydroFluoroCarbon indicates that the refrigerant is comprised of Hydrogen, Fluorine, and Carbon. A blend that contains different HFCs is considered an HFC refrigerant.
HFO refers to the chemical composition of the refrigerant. HydroFluoroOlefin indicates that the refrigerant is comprised of Hydrogen, Fluorine, Carbon, and that there is at least one unsaturated double bond between two carbons (olefin structure). A blend of an HFO with another type of refrigerant is typically combined with a slash (example: HFC/HFO).