What type of refrigerant is commonly phased out due to environmental concerns?

R-22 is commonly phased out due to significant environmental concerns, specifically its contribution to ozone depletion. This refrigerant, which has been widely used in residential air conditioning systems and heat pumps, contains hydrochlorofluorocarbons (HCFCs) that harm the ozone layer. The phase-out of R-22 is a part of the global effort to protect the environment, adhering to the Montreal Protocol, which aims to reduce substances that deplete the ozone.

In contrast, alternatives such as R-410A, R-134A, and R-407C have been developed with improved environmental profiles. R-410A, for example, does not contain chlorine and thus is less harmful to the ozone layer. While R-134A has also been targeted for reduction due to its global warming potential, it has not faced the same level of regulatory pressure as R-22. Therefore, the correct identification of R-22 as the refrigerant being phased out is essential in understanding the changes in HVAC practices focused on environmental responsibility.