The HVAC industry is in the midst of another refrigerant transition, as the federal AIM Act mandated an 85% phasedown of HFC refrigerants by 2036. Unlike the previous transition from R-22 to R-410A, which were both nonflammable (A1) refrigerants, this one involves alternatives that are lower flammability (A2L), but many state building codes do not yet allow their use in stationary comfort cooling equipment.
Several states have already updated their building codes to allow the use of A2L refrigerants in larger air conditioners and heat pumps, but others are waiting for the international code bodies to release their 2024 mechanical codes. In the U.S., states usually adopt mechanical codes from either the International Code Council (ICC) or the International Association of Plumbing and Mechanical Officials (IAPMO). Both will soon complete their 2024 mechanical codes, which may include the use of A2L refrigerants, and contractors should become familiar with those possible provisions.