A Pex vs B Pex [Which PEX Tubing is Better for Plumbing?]

PEX (cross-linked polyethylene) tubing has become increasingly popular in recent years for use in residential and commercial plumbing applications. There are a few different types of PEX tubing on the market, with the two most common being A PEX and B PEX. Both offer advantages, but there are some key differences between the two that plumbers and homeowners should understand when deciding which to use.

Here is an in-depth comparison table for A PEX vs B PEX:

Comparison CriteriaA PEXB PEX
Manufacturing MethodEngel method using peroxideSilane method with moisture-cured silicone
Temperature Rating-40°F to 180°F40°F to 200°F
FlexibilityLess flexible, rigid tubingMore flexible tubing
AvailabilityVery common, widely availableLess common, limited suppliers
InstallationRequires expanders for connectionsPush-fit or compression fittings
Pipe Supports32 inches between supports48 inches between supports
Resistance to FreezingExcellent, can withstand freezing tempsModerate, should not be exposed to freezing
DIY Friendly InstallMore difficult, requires expandersEasier, push-fit connections
Tubing ConnectionsExpanded tube ends use clampsPush-fit or compression fittings
Ability to BendRequires more elbow joints to bendCan bend smoothly without fittings
Pressure Rating100 psi @ 180°F, 160 psi @ 73°F100 psi @ 200°F, 160 psi @ 73°F
Codes ApprovalCommon, approved in major plumbing codesLess common, may need local approval
Chemical ResistanceExcellent, resistant to most chemicalsExcellent, resistant to most chemicals
ColorCommonly red, blue, whiteCommonly red, blue, white
Main ApplicationsCold and hot water lines, underground runsInterior water lines, inaccessible locations

What is PEX Tubing?

PEX stands for cross-linked polyethylene. It is a flexible plastic tubing that is specially engineered to be more durable and withstand higher temperatures than traditional plumbing materials like copper.

The “cross-linking” refers to the chemical bonding process that gives PEX its superior strength and flexibility. This process bonds the polyethylene polymer chains together to change the structure.

The cross-linking makes the tubing more resistant to heat, freezing temperatures, chemicals, and abrasion. It also makes PEX more flexible and able to bend around corners without kinking.

Benefits of Using PEX for Plumbing

There are several reasons why PEX has become a top choice for residential and commercial plumbing systems:

  • Flexible – The flexible tubing makes installation much easier by reducing the need for fittings and allowing the tubing to maneuver around obstacles.
  • Durable – PEX tubing is highly durable and resistant to typical issues like corrosion and buildup. It can last over 30 years with proper installation.
  • Freeze resistant – The flexible material can expand and contract with temperature changes without bursting. This makes it suitable for cold climate installations.
  • Chemical resistant – PEX tubing withstands exposure to chemicals and minerals better than copper, CPVC, or PVC. It won’t corrode or leach chemicals.
  • Thermal resistance – PEX retains its integrity and flexibility in both hot and cold water temperatures. It’s rated for high-temperature applications up to 200°F.
  • Noise reduction – The elasticity of PEX dampens vibrations and water hammer effects, resulting in quieter plumbing.
  • Cost – PEX tubing is relatively affordable compared to materials like copper. Lower material and labor costs make PEX an economical option.

Types of PEX Tubing

While all PEX tubing shares the same base material and cross-linking properties, there are differences when it comes to manufacturing methods. The two most common types available are:


  • Manufactured using the Engel method
  • Uses peroxide to solidify the outer layer
  • More rigid/less flexible
  • Wider temperature rating (-40°F to 180°F)
  • Often cheaper than B PEX


  • Manufactured using the Silane method
  • Uses moisture-cured silicone for outer layer
  • More flexible tubing
  • Typical rating of 40°F to 200°F
  • Generally more expensive than A PEX

The manufacturing method affects the tubing’s flexibility, temperature resistance, and cost. But both A PEX and B PEX offer enhanced durability and performance over traditional piping materials.

A Pex vs. B Pex: Key Differences

When trying to choose between A PEX and B PEX tubing, there are a few key differences to consider:

Temperature Rating

  • A PEX has a wider temperature range, handling temperatures from -40°F to 180°F. This makes it ideal for extreme cold climate applications.
  • B PEX has a narrower range from 40°F to 200°F. The inability to withstand freezing temps limits B PEX to indoor uses.


  • A PEX tubing is slightly stiffer and less flexible. Tighter bend radiuses are required during installation.
  • B PEX offers greater flexibility and ability to maneuver around corners and obstructions. It’s easier to work with overall.


  • A PEX generally costs less per foot than B PEX tubing. This can add up with long pipe runs.
  • B PEX is the more expensive option in most cases. The proprietary manufacturing increases costs.


  • A PEX tubing and fittings are widely available from most plumbing suppliers due to the lower cost.
  • B PEX may have limited availability, as some manufacturers promote their own branded B PEX systems.


  • A PEX requires special expanding tools for connections. The stiff tubing is more difficult to work with in tight spaces.
  • B PEX can use push-fit or compression fittings for faster, simpler DIY connections. The flexibility also makes install easier.

Pipe Support

  • A PEX should be properly supported every 32 inches due to its rigidity. This increases installation time.
  • B PEX only needs support every 48 inches, allowing for simpler, faster runs.

Choosing Between A PEX vs B PEX

When selecting a PEX tubing system, here are some general guidelines to consider:

  • Use A PEX for extreme temperature environments (like attics, crawl spaces, outdoor runs). It withstands freezing better.
  • Choose B PEX for more accessible, warmer climate applications where flexibility and ease of installation are beneficial.
  • Consider the availability of fittings & tools needed for each type in your area. This can drive costs.
  • Weigh upfront material costs vs. labor costs for your specific project. B PEX needs less support but costs more per foot.
  • Consult local codes – some may approve only A PEX or B PEX based on local conditions and contractor preferences.

Both A PEX and B PEX are durable, code-approved options for plumbing systems. Take into account the temperature, flexibility, cost, and availability factors to select the best PEX tubing type for your particular plumbing application. A reputable plumber can also provide guidance on selecting the right PEX products to meet the needs of your residential or commercial project.

Common PEX Pipe Problems

While PEX offers many benefits, there are some potential issues to be aware of:

  • Kinks – Sharp bends and excessive twisting can cause kinks that restrict water flow. Proper bending radius and supports help.
  • Crushing – Damage from impact, heavy objects, or overtightened fittings can deform the tubing and reduce the interior diameter.
  • UV light degradation – Sunlight exposure over time can cause PEX tubing to become brittle and crack. Use UV-resistant or insulated PEX.
  • Fitting failures – Poor installation practices can lead to leaks or fittings pulling off. Follow manufacturer guidelines.
  • Restricted flow – Buildup on the interior walls of PEX can gradually reduce water pressure over time.
  • Permeation – Chemicals like chlorine, present in drinking water, can potentially leach through PEX tubing walls long-term.
  • Freezing – Expanding frozen water inside can rupture PEX. Ensure pipes are below frost line or insulate properly.
  • Overheating – High temperatures beyond the rating of the PEX tubing can cause melting or burning.

Following best practices for PEX installation and avoiding damage can help minimize potential issues. Annual inspections are recommended to check condition and water flow.

Maintaining and Repairing PEX Plumbing Systems

Like any plumbing system, PEX lines and fittings need occasional maintenance. Here are some tips:

  • Inspect PEX tubing runs for damage, wear, leaks, kinks, or flow issues. Schedule annual check-ups.
  • Check that fittings are still secure. Look for signs of leaks at connections.
  • Confirm proper support is still in place. Add hangers if needed to prevent sagging.
  • Remove built-up scale or mineral deposits. Descaling solutions can restore flow.
  • Monitor water pressure and volume to the fixtures. Declines may indicate PEX wear or interior deposits.
  • Have a professional flush PEX water lines periodically to clear any debris or buildup.
  • To add new plumbing branches, use T-fittings to avoid cutting the PEX lines.

For repairs:

  • Patch small punctures in PEX using epoxy glue. For larger holes, cut out and replace the damaged section.
  • Replace any loose, broken, or leaking fittings. Drain plumbing lines before working.
  • To remove fittings, cut the PEX on both sides and drain that section. Use new tubing and push-fit connections.
  • When re-routing lines, take advantage of the flexibility – make gradual bends where possible to avoid joints.

Frequently Asked Questions

Is PEX approved for use with drinking water?

Yes, both A PEX and B PEX tubing are certified for potable water use and meet plumbing code standards. They won’t contaminate drinking water when properly installed.

Can PEX pipes withstand hot water?

PEX is rated for high temperature applications, withstanding up to 200°F continuously for B PEX and 180°F for A PEX. Suitable for hot water heaters and lines.

Is PEX easy for DIY homeowners to install?

B PEX can be installed using simple push-fit connections. A PEX requires expanders to join fittings. With proper planning, PEX is DIY-friendly.

How long does PEX plumbing last compared to copper?

Properly installed PEX can last 30+ years. PEX doesn’t corrode like copper. But copper may outlast PEX in certain applications.

Can PEX tubing be used outside?

Outdoor burial is not recommended. Insulated PEX can be used in exterior exposed runs like hydrant lines if protected from UV light damage.


PEX tubing offers homeowners and plumbers an attractive option for water supply lines. Both A PEX and B PEX provide durability, leakage resistance, and flexibility that can simplify installations. Factors like temperature rating, bend radius, fittings, and cost help determine whether A PEX or B PEX is the best choice for the project. With proper installation and occasional maintenance, PEX plumbing systems can provide reliable service for over 30 years. The reduced complexity compared to traditional metal pipes makes PEX a go-to solution for many plumbers today. By understanding the differences between A PEX and B PEX, homeowners can make informed decisions when selecting plumbing materials.

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