What Refrigerant is Used in Home Air Conditioners?

The types of refrigerant used in home air conditioners include ammonia, sulfur dioxide, hydrocarbons and R series refrigerant gas.


Ammonia is the oldest known refrigerants, producing cooling by mechanical movements. The problem with ammonia vapors are that they are flammable, toxic and can explode. Sulphur dioxide (SO2) is no longer in use although it is present in older home air conditioning units. SO2 is not flammable or explosive but moisture that develops in conjunction with the chemical compound will damage the cooling units and cause them to corrode.


Hydrocarbons such as methane, propane and isobutene are sold as bottled gases and fuels. Methylene chloride is a less flammable hydrocarbon used as a refrigerant. HCFC or CFC refrigerants are safer hydrocarbons because they are non-combustible and non-toxic.

R Series Refrigerant Gases

R series refrigerant gases such as R-410A, AZ-20, SUVA R-134A and R-407C are newer gases used in air conditioners, replacing Freon. They are multifunctional in nature, used in medications like propellants in bronchodilators, for asthmatic treatments like Xopenex.


Water is also a commonly used refrigerant in a home air conditioner. It is still frequently used and is effective in the heat transfers for air-conditioning systems such as air-cooled coolers. It is most effective and works successfully in an environment that has a low level of humidity.