PEX pipe has revolutionized plumbing in recent
decades, becoming a dominant choice for residential water supply lines. But like
any material, it comes with its own set of pros and cons. Understanding these is
crucial for homeowners, builders, and DIY enthusiasts considering PEX
plumbing.
PEX Pipe Advantages
Exceptional Flexibility:
Benefit: PEX can bend around corners and obstacles with minimal need for
elbow fittings. This significantly simplifies installation, especially in tight
spaces or complex layouts.
Result: Faster installation times, lower labor costs, fewer potential leak
points (at fittings), and reduced flow resistance.
Freeze Resistance:
Benefit: PEX is more forgiving if water inside freezes compared to rigid
pipes like copper or CPVC. It can expand significantly without rupturing,
potentially avoiding costly bursts.
Result: Reduced risk of catastrophic water damage in colder climates,
though freezing should still be prevented.
Corrosion and Scale Resistance:
Benefit: Unlike metal pipes (copper, iron), PEX is completely immune to
corrosion from water or soil chemicals. It also resists mineral scale buildup
internally.
Result: Longer lifespan potential, consistent water flow over time, and
elimination of "pinhole" leaks common in corroding copper. Maintains water
quality without metallic taste.
Quieter Operation:
Benefit: The plastic material dampens water flow noise and water hammer
shock better than rigid metal pipes.
Result: Quieter plumbing system operation within the home.
Faster & Simpler Installation:
Benefit: The flexibility, combined with reliable push-to-connect
(SharkBite), compression, clamp (cinch), or expansion connection systems, makes
installation much quicker than soldering copper or gluing CPVC.
Result: Significant time and labor savings during new construction or
renovations. Often more DIY-friendly (especially with push-fit fittings).
Cost-Effective:
Benefit: PEX tubing itself is generally less expensive than copper pipe.
Combined with lower labor costs due to faster installation, the overall project
cost is often significantly reduced.
Result: More budget-friendly plumbing solutions without sacrificing
performance.
High-Temperature Tolerance:
Benefit: Modern PEX is rated for standard residential hot water
temperatures (up to 200°F for many types under pressure).
Result: Perfectly suitable for hot and cold water supply lines throughout
the home.
PEX Pipe Disadvantages
UV Sensitivity:
Drawback: PEX degrades when exposed to ultraviolet (UV) light from the
sun.
Implication: Cannot be used outdoors or in areas exposed to direct
sunlight. Must be stored indoors away from sunlight and installed within
protected walls, floors, or ceilings. If run outdoors, it must be shielded
completely.
Vulnerability to Rodents and Pests:
Drawback: Some rodents (rats, mice) and insects may chew through PEX pipe
under certain circumstances, though this isn't extremely common.
Implication: Requires extra precautions in areas prone to infestations
(sealing entry points, using protective sleeving in vulnerable areas like
attics/crawlspaces).
Cannot Be Recycled (Easily):
Drawback: The cross-linking process makes PEX difficult to recycle through
standard municipal plastic recycling streams.
Implication: Contributes to landfill waste unless specific (and often
limited) PEX recycling programs are available locally. Less environmentally
friendly at end-of-life compared to highly recyclable copper.
Potential Permeability Concerns:
Drawback: Some types of PEX and certain conditions might allow very low
levels of outside substances (like petroleum products, pesticides, or oxygen) to
permeate the pipe wall.
Implication: Generally not a concern for standard residential potable water
under normal conditions. However, it necessitates careful installation away from
potential chemical contamination sources. Oxygen permeability (especially in
PEX-A) can be a concern for closed-loop heating systems (requiring barrier
PEX).
Connection Reliability (Dependent on Method):
Drawback: The long-term reliability hinges entirely on the quality of the
fittings and the installation technique. Some connection methods (like stab-in
fittings) have faced historical criticism, though modern certified fittings are
robust.
Implication: Requires proper training and adherence to manufacturer
instructions. Using non-certified fittings or improper tools is a significant
risk. Brass fittings can also be a point of potential corrosion if
low-quality.
Higher Cost than PVC:
Drawback: While cheaper than copper, PEX is typically more expensive than
standard Schedule 40 PVC pipe.
Implication: For cold-water drainage applications (where PVC is suitable),
PVC remains the more economical choice. PEX is primarily for pressurized supply
lines.
Conclusion: A Strong Contender with Smart Application
PEX pipe offers compelling advantages – flexibility, freeze resistance,
corrosion immunity, ease of installation, and cost savings – that make it an
excellent choice for the vast majority of residential hot and cold water supply
lines. Its disadvantages (UV sensitivity, potential rodent issues, recycling
difficulty) are generally manageable with proper installation practices and
material handling.
When choosing PEX:
Use it Indoors: Keep it protected from sunlight.
Buy Quality: Use tubing and fittings certified to relevant standards
(WATERMARK,CE,GOST).
Install Correctly: Follow manufacturer instructions meticulously for your
chosen connection method.
Consider the Environment: Be mindful of installation near potential
contaminants and the end-of-life disposal challenge.
For most modern plumbing jobs, PEX's significant benefits far outweigh its
manageable drawbacks, solidifying its position as a leading plumbing material.
Always consult local building codes and consider professional installation for
complex projects.
