PEX vs copper pipe: which should you use?
Short answer: PEX is cheaper, faster to install and more freeze-tolerant, which makes it the default for most concealed water lines and repipes today. Copper lasts longer, shrugs off heat and UV, and is fully recyclable, so it still wins for exposed, outdoor and high-temperature runs. Plenty of homes use both.
At a glance
| PEX | Copper | |
|---|---|---|
| Up-front cost | Lower (material + labour) | Higher (≈2–3× material) |
| Install speed | Fast — flexible, fewer fittings | Slower — cut & solder joints |
| Lifespan | ~25–50 years (newer) | 50+ years (proven) |
| Freezing | Expands — more freeze-tolerant | Can burst |
| High heat / fire | Temperature-limited | Excellent |
| Outdoors / UV / exposed | No (UV-sensitive) | Yes |
| Corrosion | Doesn't corrode | Can pinhole in acidic water |
| Recyclable | No | Yes |
Cost: PEX is cheaper to buy and to fit
On material alone, copper typically runs two to three times the price of PEX, and the gap widens once labour is counted. PEX is flexible, so a plumber can run a single line from a manifold to a fixture with far fewer joints — no cutting, reaming and soldering at every turn. For a whole-house repipe, that speed is often the deciding factor.
Lifespan and durability
Copper has a 50-plus-year track record and is the benchmark for longevity. PEX is newer, with a realistic service life commonly quoted at 25–50 years; it doesn't corrode, which is a real advantage where water is acidic and copper can develop pinhole leaks. The trade-off is PEX's shorter history and sensitivity to UV light and rodents.
Cold climates and freezing
PEX can expand as water freezes and is far less likely to split than rigid copper, which is why it's popular in cold regions. It is not freeze-proof — insulation and proper routing still matter — but it is more forgiving.
Heat, exposure and where copper still wins
Copper handles high temperatures and direct sunlight, so it remains the choice for exposed runs, outdoor lines, and connections at the water heater (PEX is often joined to a short copper or metal nipple there). It's also the only one of the two that's recyclable, and some buyers and inspectors still prefer it on sight.
Which should you choose?
For a budget-conscious repipe, a cold climate, or long concealed runs, PEX is usually the practical pick. For exposed plumbing, outdoor lines, high-heat spots, or maximum longevity and resale appeal, copper earns its premium. Whatever you choose, both must be approved for potable water in your area — check the plumbing code your local Authority Having Jurisdiction (AHJ) adopts, as a few jurisdictions still restrict certain materials.
Common questions
- What is better to use, PEX or copper?
- Neither is universally better. PEX wins on cost, speed of installation and freeze resistance, so it's popular for repipes and cold climates. Copper wins on longevity, high-temperature tolerance, recyclability and exposed/outdoor runs. Many homes use both — PEX in walls, copper at the water heater and exposed connections.
- Why do insurance companies not like PEX plumbing?
- Most hesitation is a holdover from earlier plastic systems that failed — polybutylene and some Kitec fittings — which PEX is sometimes confused with. Modern PEX-a/PEX-b is widely accepted by codes and insurers, but a few companies still ask about it, so confirm with your insurer before a full repipe.
- Why did they stop using copper pipes in houses?
- Copper hasn't failed — it's mostly cost and labour. Copper material is roughly 2–3× the price of PEX, and it's slower to install (cut, ream, solder every joint). PEX is cheaper, faster and freeze-tolerant, so builders increasingly choose it for concealed water lines.
- What is the downside to PEX plumbing?
- PEX degrades in sunlight (UV), so it can't be used outdoors or exposed; rodents can chew it; it isn't recyclable; and it has a shorter real-world track record than copper. It also can't be used right at very high temperatures, so copper or a metal nipple is often used at the water-heater connection.
Reference & education only. Not professional, engineering, or code-compliance advice. Estimates are based on published model codes; local amendments and your Authority Having Jurisdiction (AHJ) govern. Always verify against the current adopted code and a licensed professional before doing work.
Last reviewed 2026-06.