R-32

R-32 (difluoromethane, HFC-32) is a single-component HFC refrigerant with GWP of 675 and zero ODP. It is not a blend — 100% R-32 — which eliminates fractionation concerns and simplifies charging, recovery, and reclamation. Its GWP places it just below the 750 threshold required for new residential AC equipment under AIM Act Technology Transitions rules.

R-32 is the dominant residential AC refrigerant in Japan, much of Asia, and Europe. Japanese manufacturers including Daikin, Mitsubishi, and Fujitsu have used R-32 extensively in their global split system product lines since 2011-2014. The global experience base with R-32 is substantial — hundreds of millions of units are operating worldwide.

R-32 has slightly higher operating pressures than R-410A and better energy efficiency characteristics at higher ambient temperatures. Its volumetric cooling capacity is approximately 15% higher than R-410A, allowing smaller system designs with equivalent capacity.

R-32 carries A2L safety classification due to its mild flammability — the lower flammability limit (LFL) is approximately 14.4% volume in air, and its minimum ignition energy is higher than most flammable substances, meaning it is difficult to ignite in typical conditions. A strong ignition source is required.

The A2L designation requires the same equipment certifications and installation practices as R-454B. Equipment must be UL 60335-2-40 certified, and installation must comply with ASHRAE 15-2022 provisions for A2L refrigerants. For technicians, A2L training covering R-32 service practices is the prerequisite for working on R-32 equipment.

From a practical field perspective, the risk profile of R-32 is well-understood through decades of global use. The Australian and New Zealand experience is particularly relevant for guidance — both countries adopted R-32 years before the US market and developed practical A2L service training programs that inform the US approach.