In HVAC refrigerants, what does R-22 refer to?

• A. A type of compressor
• B. A thermostat model
• C. A pipe material
• D. A refrigerant type historically used; phased out in newer systems

Answer: (D)

R-22 is a refrigerant type, not a component or material. It’s a chemical refrigerant (chlorodifluoromethane) that was widely used in air conditioning and refrigeration systems for many years. Environmental regulations led to a gradual phase-down of R-22 because it contains chlorine that harms the ozone layer. As a result, newer equipment is designed to run on alternative refrigerants, such as R-410A, rather than R-22. In practice, older systems may still use or be serviced with recovered R-22, but new installations should use different refrigerants. This is why the correct description is that R-22 is a refrigerant type historically used and phased out in newer systems.