Which is Better PEX A or PEX B?

A very common question among the plumbers and homeowners that which is better PEX A or PEX B.

The question is obvious because nobody wants to change the pipework after a few months or years.

The truth is A, B or C after PEX are just the identifier for the manufacturing process, nothing to do with quality or performance.

Also, all the manufacturing processes must meet the same international standard like SDR9 dimensional standard, ASTM F876 and ASTM F877 standards.


Despite the similarities, there are certain differences as the manufacturing process is different and the companies are different.

Manufacturing ProcessPeroxide (Engel) methodSilane or Moisture Cure method
Cross-linking RatioHighest degree of cross-linking among all PEX types.Lower degree of cross-linking ratio than PEX A.
CrystallinityLower crystallinityHigher crystallinity
FlexibilityHighestStiffer than PEX-A
Coil MemoryNo coil memoryNoticeable coil memory
Bursting PressureLower than PEX BHighest among all PEX
Wall ThicknessHigher than PEX BLower than PEX A
ResistanceLower than PEX BHighest oxidative & chlorine resistance
ManufacturersUponor, Mr. PEX, RehauViega, Watts,Everhot
PriceLowest among all PEX100-160% higher than PEX-B

Which is Better PEX A or PEX B?

As you can see in the table, there are differences between the PEX types.

But Company made them in a way so that the every PEX can provide almost similar result.

For example: PEX A has a lower crystallinity than PEX B. So, PEX A has got lower density and lower strength. To cope up with this PEX A is made with higher degree of cross linking and wall thickness.

Despite the differences, all the PEX has minimum minimum bending radius, temperature & pressure ratings, pipe wall thickness and ID/OD dimensions.

So, as a installer or hose owner what you need is checking the minimum performance requirements as specified by American Standards and Building Codes.

Also make sure the PEX types are third-party certified for end use application.

1. Radiant Floor Heating: Make sure pipe meet the ANSI/NSF 14 standards & marked with nsf-rfh or the actual standard.

2. Plumbing Pipework: Should be NSF-approved and marked with pw-G, NSF-61-G. Also meet the ANSI/NSF61 & ANSI/NSF372 standards, lead-free standards.

3. Chlorinated Water: Must meet ASTM F2023 compliance and imprinted on the pipe.

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