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Old copper pipes can corrode, leak, and be costly to repair, just ask me how I know. Many homeowners are switching to PEX (a.k.a. cross-linked polyethylene) because it's flexible, easier to install, and resistant to corrosion. Unlike rigid copper, PEX is flexible tubing and bends around corners, reducing the need for elbow fittings and minimizing the chances of leaks. If you're considering replacing your old water lines, or replumbing due to a residential remodel, PEX could be the right choice.
Why Homeowners Are Choosing PEX Over Copper
PEX is gaining popularity for good reason. Compared to the price of copper, it's more affordable, easier to install, and better suited for modern plumbing needs.
- Cost Savings – PEX is significantly cheaper than copper pipe systems, both in material costs and installation. Copper prices fluctuate, but PEX remains consistently lower in price.
- Flexibility – PEX bends around obstacles, so you don’t need as many elbows and fittings. Fewer connections mean fewer potential leak points.
- Corrosion Resistance – Unlike copper tubing, PEX won’t corrode or develop pinhole leaks over time, making it a long-lasting solution.
- Easier Installation – You don’t need to solder pipes together. PEX connections can made with simple crimping, expansion, or push-fit connectors depending on the type of PEX you're using.
- Better for Cold Climates – PEX can expand slightly if water freezes inside, making it less likely to burst compared to copper.
While copper has a long life expectancy, the high cost and risk of corrosion make PEX a smart alternative, especially for homeowners who want an easier, more affordable option.
What’s Involved in Replacing Copper with PEX?
Replacing copper systems with PEX pipes isn’t as complicated as it might seem, but it does require planning and some special installation tools. The installation process usually involves shutting off the water supply, removing old copper lines, and running new PEX pipes.
Tools and Materials Needed:
- PEX tubing (red for hot water, blue for cold water, or white for both)
- PEX cutter
- Crimping tool or push-fit connectors
- Crimp rings a.k.a. clamp rings
- PEX expansion tool (if using PEX-A and expansion fittings)
- Pipe hangers and supports
- Shut-off valves
Planning Considerations
Before starting, it’s important to map out the new water supply line route. PEX pipes can run longer distances with fewer fittings, but you’ll need to account for expansion and secure the tubing properly. Many homeowners opt for a home-run system, where each fixture has its own dedicated line from a central manifold, providing better water pressure and control.
You’ll also need to decide on the type of PEX, which determines the types of fittings: crimp, clamp, push-to-connect, or expansion. PEX-A and PEX-B are the main considerations. PEX-A is more flexible and expandable, uses expansion-style fittings, and requires a PEX expansion tool. The interior diameter does not restrict water flow like PEX-B fittings. PEX-B is less flexible than PEX-A, and uses insert-type fitting that requires compression connectors, either crimp or clamp style. Both PEX-A and PEX-B are compatible with push-fit connectors. Crimp or clamp compression connector fittings are the most common, while push-on connector fittings are great for DIYers who want ease of installation without special tools.
Can You Replace Copper with PEX Pipes Yourself?
For many homeowners, PEX plumbing installations are a manageable DIY project. If you have good access and are comfortable cutting and connecting water pipes, you can likely handle it. The most important steps are shutting off the water, properly securing the PEX pipes, and testing for leaks before finishing the job.
That said, if your plumbing system is complex, involves cutting sections of drywall out of finished walls, finding access panels, and major rerouting, hiring a professional plumber might be a better choice. Experienced plumbers can complete the vast majority of jobs quickly and handle any unexpected challenges, such as hidden leaks or difficult pipe runs. You also should check with your local building codes and rules regarding residential plumbing, plumbing codes, and the need to use licensed plumbers and permits. You don't want to find out about code issues as part of a future home inspection.
Tips for a Smooth Installation:
- Use a PEX cutter to ensure clean, straight cuts.
- Don’t over-crimp fittings; follow the manufacturer’s guidelines.
- Secure PEX tubing every 32 inches horizontally and every 4 linear feet vertically.
- Leave room for expansion, especially for long runs.
- Always test for leaks before closing up walls or ceilings.
FAQ
Does PEX reduce water pressure?
No, but it depends on the installation. PEX-B fittings have a slightly smaller inside diameter than copper, which can slightly reduce flow rate. However, a well-designed system, especially a home-run manifold setup, can maintain strong water pressure.
Can PEX be connected to existing copper pipes?
Yes. You can use push-to-connect, solder, or threaded connector to transition between copper and PEX. This makes partial replacements or repairs easier without redoing the entire plumbing system.
