PEX vs Copper Pipe
PEX costs less, installs with far fewer joints, and tolerates freezing much better because it expands rather than splits. Copper lasts longer under ideal conditions and handles heat better. For most repipes today, particularly in freezing climates, PEX is the pragmatic choice.
Side by side
| PEX | Copper | |
|---|---|---|
| Material and labour cost | 30 to 40 percent less | Higher on both |
| Freeze tolerance | Expands, often survives | Splits readily |
| Joints required | Few; flexible runs bend around obstacles | Many; every direction change is a fitting |
| Expected life | 40 to 50 years, warranties typically 25 | 50 to 70 years in good conditions |
| Corrosion resistance | Immune to the chemistry that pits copper | Vulnerable to acidic and aggressive water |
| UV exposure | Degrades; cannot be used unprotected outdoors | Unaffected |
| Rodent damage | Vulnerable in crawlspaces and attics | Resistant |
| Recyclable value | Minimal | Significant scrap value |
Costs are national editorial estimates for orientation, not quotes.
PEX
Pros
- Substantially lower installed cost
- Expands when water freezes, which frequently prevents a burst
- Flexible, so a run can bend around obstacles with no fittings
- Immune to the acidic water chemistry that causes copper pinholes
- Quieter, with no water hammer transmission through rigid pipe
Cons
- Degrades under UV, so it cannot be used outdoors or stored in sunlight
- Rodents can chew through it in crawlspaces and attics
- Cannot connect directly to some water heaters without a metal transition
- Shorter track record than copper, though now several decades long
Copper
Pros
- Very long service life where water chemistry is favourable
- Handles high temperatures without limitation
- Naturally biostatic surface
- Unaffected by UV, rodents, and physical abrasion
- Preferred by some buyers, which has a small resale effect
Cons
- Splits readily when water inside freezes
- Vulnerable to pinhole corrosion in acidic or aggressive water
- Every joint is a soldered or pressed connection and a potential failure point
- Significantly more expensive in both material and labour
- Attracts theft from vacant and under-construction properties
In an emergency
This is where the two genuinely diverge. A frozen copper line splits; a frozen PEX line often expands and survives. In any climate with hard freezes, that difference alone accounts for a large share of the emergency calls this site exists to describe. Conversely, in a crawlspace with a rodent problem, PEX introduces a failure mode copper does not have.
The cost picture
A PEX repipe typically runs 30 to 40 percent below copper for the same house, and the gap is mostly labour: fewer joints and faster installation. Over a fifty-year horizon copper may last longer in favourable conditions, but in acidic water it frequently does not last as long as PEX would.
Our recommendation
For most repipes, PEX. It costs less, it survives freezes that split copper, and it is immune to the water chemistry that causes pinhole leaks. Copper remains a reasonable choice where water chemistry is favourable, where exposed runs need physical durability, or where a homeowner specifically wants it. Neither is a wrong answer; PEX is simply the better default now.
PEX suits
Repipes in freezing climates, homes with acidic or aggressive water, budget-sensitive projects, and any retrofit where flexibility reduces wall opening.
Copper suits
Exposed runs needing physical durability, high-temperature applications, homes with known rodent problems in pipe chases, and owners who specifically prefer it.
Frequently asked questions
Is PEX safe for drinking water?
Yes. PEX is certified to NSF/ANSI 61 for potable water and approved in essentially every US plumbing code. Some people notice a faint taste in the first few weeks after installation, which dissipates once the system has been flushed and used normally.
Will PEX really not burst when it freezes?
It tolerates freezing far better than copper because the tubing expands and returns to shape, but it is not freeze-proof. A sustained hard freeze in a closed system can still cause a failure, usually at a fitting rather than mid-run. Think of it as buying margin, not immunity, and insulate exposed runs regardless.
Does copper pipe affect resale value?
Marginally, and less than it used to. Some buyers and agents still perceive copper as premium. What genuinely affects value is having galvanized or polybutylene, both of which inspectors flag and buyers negotiate on. A documented PEX repipe closes that issue completely.
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