R-22 is the common name for hydro-chlorofluorocarbon (HCFC). R-22 has been used as a refrigerant by HVAC manufacturers for over 40 years, but studies in the past decade have shown that the chlorine in HCFCs contribute to ozone depletion. For this reason, the United States Clean Air Act has set a target date for January 1, 2010, on which HVAC manufacturers must cease the manufacture of products that use R-22.