A single component HCFC refrigerant, R-22 has been historically used for air conditioning, specifically in medium to low-temperature applications. Discovered in the 1970’s it becomes the most used refrigerant in the world. Talking of air conditioners installed before 2010, they are likely to have R22 as a refrigerant.
Due to low boiling point it can only be used for either low or medium temperature application such as domestic, farm freezers and in small industries. Systems using this refrigerant should contain minimum CR (Compression Ratio).
Although R22 with an insight to the whole market couldn’t possibly be fade out quickly but still after Montreal Protocol, an international treaty had been signed, in which EPA (Environmental Protection Agency) declared R22 as Ozone layer depleting refrigerant and since then its production as well imports begin to ride at the edge of extinction.