As of 2026, the EPA has strictly limited R404A in new commercial refrigeration systems (supermarkets, cold storage). It has one of the highest GWPs (3,922) and is a primary target for the phase-down under the AIM Act.

R448A (Solstice® N40) or R449A are the U.S. industry favorites. These replacements drop the GWP by 60% and usually offer better energy efficiency without needing a total equipment overhaul.

It uses POE oil, which is hygroscopic (it aggressively absorbs moisture from the air). In the U.S. South, leaving a 404A system open for even 15 minutes can lead to acid formation and catastrophic compressor burnout.