This tech tip was written by Dr. Chuck Allgood from Chemours. Thanks, Dr. Chuck!

As the ramp-up of new AC units and heat pumps with low-GWP refrigerant R-454B accelerates, it may be useful to look at some of the basic properties of R-454B refrigerant as compared to the legacy gas it’s replacing: R-410A. This tech tip is a brief review of some of the more important aspects of R-454B vs. R-410A—compared side by side.

Head to Head: R-454B vs. R-410A

Refrigerant Cylinders: While R-410A jugs were pink, the R-454B will be off-white, with a red strip (denoting the A2L (lower flammability) class. R-454B cylinders will come with left-hand threads and a pressure relief valve instead of the old rupture disk. The fill weight will be 20 lbs, as opposed to 25 lbs for R-410A.

PT Charts: The PT curves for R-454B and R-410A are very similar, but for best performance, use the appropriate chart or app for your specific application. 

GWP: The lower GWP of 466 for R-454B is ~22% of R-410A's GWP (2088).

Safety Classification: Both are Class A (lower toxicity) refrigerants, with R-454B being Class 2L (lower flammability) compared to R-410A's Class 1 (no flame propagation).

Servicing: R-454B is to be used only in new systems designed for R-454B. Legacy systems designed for R-410A should only be serviced with R-410A.  

Temperature Glide: Both refrigerants have minimal glide: R-454B ~2°F and R-410A ~1°F.

Topping Off:  It is acceptable to top off systems with either gas after repairing leaks.

Lubricants:  Both R-454B and R-410A systems will use POE-based lubricants, which should be handled carefully to avoid introducing moisture to the system.

Best Practices:  Many best practices recommended for R-410A, such as purging, leak checks, and evacuation, are now required for R-454B and other A2L refrigerants.

Recovery Machines and Vacuum Pumps:  For servicing R-454B or other A2L systems, use A2L-rated equipment.

Conclusion

While there are some clear differences between R-454B and R-410A, the practical ones are relatively minor. The cylinders can help you tell them apart, but the thermodynamic properties and performance will be close to the same. R-454B just has a very clear GWP advantage over R-410As. In any case, make sure you're using tools meant for A2L refrigerants and following best practices during installation and service.

—Dr. Chuck Allgood

P.S. – Don Gillis compared R-454B and R-32 to R-410A in depth in another tech tip. You can read his article HERE.