What Kind of Freon Does a Central Air Unit Take?

The type of refrigerant used in a central air conditioning system depends on when the unit was manufactured.


Several types of refrigerants are used for air conditioners.Several types of refrigerants are used for air conditioners.
In an effort to reduce chlorine emissions into the atmosphere, laws mandated phasing out Freon in favor of more environmentally safe products. Central air units typically have a service tag on the outside condensing unit that indicates the type of refrigerant in use in that system.

R-22 refrigerant, also known as Freon, was the coolant of choice for air conditioning systems for about forty years. But R-22 contains hydrochlorofluorocarbons (HCFC), which damage the Earth’s ozone layer. After Dec. 31, 2009, U.S. law prohibited manufacturers from producing air conditioners that use R-22. In addition, those companies that produced R-22 refrigerant were limited to manufacturing only enough to satisfy the needs of existing systems.


Manufacturers developed less harmful substitutes for R-22, the most common of which is R-410A. This blend, while still including chlorine as an ingredient, is less harmful to the ozone layer. R-401A sells under a variety of trade names and similar products are also on the market. The U.S. Environmental Protection Agency maintains a list of approved R-22 substitute refrigerants, which includes R-410A.

Montreal Protocol

In 1987, the world’s developed nations signed an agreement to phase out HCFC contaminants. The agreement, known as the Montreal Protocol, was amended in 1992 and laid out plans for the eventual elimination of HCFCs. The United States enacted the Clean Air Act as a result. Title VI of that act calls for reduction of R-22 by 2010 and its elimination by 2020 except for what is recycled or reclaimed.

Existing Units

Air conditioners that run on R-22 are not designed to accept substitute refrigerants which typically run at higher pressures with better efficiencies. The long lead time between phase out and elimination of R-22 makes it possible to keep older units running until they must be replaced. Few R-22 units currently in operation are likely to continue operating by 2020. Those that do will be serviced with reclaimed R-22.

About the Author

Robert Korpella has been writing professionally since 2000. He is a certified Master Naturalist, regularly monitors stream water quality and is the editor of freshare.net, a site exploring the Ozarks outdoors. Korpella's work has appeared in a variety of publications. He holds a bachelor's degree from the University of Arkansas.