R404A is a near-azeotropic HFC blend (glide 0.7 K) of R125, R143a and R134a. It replaced R502 in the 1990s and became the standard refrigerant of cold rooms, blast freezing tunnels, supermarket cabinets and transport refrigeration. It works over a wide range from −45 °C to +10 °C, is well compatible with oil and is in class A1 (non-flammable, low toxicity).
Its problem is its environmental impact: GWP 3,922, meaning a 1 kg leak of R404A equals 3.9 tonnes of CO₂ emissions. The EU F-gas regulation banned refrigerants with a GWP above 2,500 in new commercial refrigeration systems from 2020 and also restricted the use of virgin gas for servicing systems above 40 tonnes CO₂e. Turkey’s Fluorinated Greenhouse Gases regulation follows the same path; the price is rising and availability is falling.
Existing systems can keep running; but in new installations and major repairs, conversion is recommended. R449A and R448A are "drop-in" alternatives that work with the same compressor and oil as R404A, with similar capacity and pressures and about a third of the GWP (1,397 and 1,387); because of their glide (4–6 K) the expansion valve setting and superheat control are reviewed. You can see R404A’s pressure–temperature chart and its comparison with the alternatives on our refrigerant page.