R507A and R404A: Two Refrigerants, Similar Applications
R507A and R404A are both HFC blends widely used in UK low-temperature commercial refrigeration. They are often specified for similar applications — frozen food display cabinets, blast freezers, cold stores and transport refrigeration — and are frequently compared when engineers specify or service low-temperature systems.
Key Differences
Composition
- R404A: Blend of R125 (44%), R143a (52%) and R134a (4%)
- R507A: Azeotropic blend of R125 (50%) and R143a (50%)
Because R507A is an azeotrope, it does not fractionate — it behaves as a single component. This makes it slightly easier to handle in terms of charging (vapour charging is acceptable) compared to R404A which requires care to prevent fractionation.
GWP
- R404A GWP: 3922
- R507A GWP: 3985
Both have very high GWPs and are subject to F-Gas phase-down restrictions. Neither is recommended for new installations in the UK.
Performance
R507A offers marginally better performance than R404A at very low evaporating temperatures (below -40°C), making it preferred for ultra-low temperature blast freezing applications. For standard commercial freezer work (-20°C to -30°C), performance differences are minimal.
The Bottom Line
For new installations, neither R404A nor R507A is recommended — switch to R448A or R449A. For servicing existing equipment, use the refrigerant the system was designed for. Our R404A 10.9 kg cylinders are available for legacy system maintenance. See our full refrigerant gas range.