Plumbing has long been out of reach, or at least difficult, for the average do-it-yourself homeowner. Taking on a plumbing remodel or repair would have meant using galvanized pipe or copper pipe and fittings for water supply systems—both difficult.
Galvanized pipe requires the user to learn complicated connection techniques. Using copper means mastering the delicate art of sweating copper fittings (the various connection points of elbows and tees that join copper pipes) with a torch and solder.
With PEX plastic pipes and push-fit type or crimp-ring fittings, plumbing is within reach of the amateur plumber. Plumbing supply stores and local home centers are well-stocked with PEX piping and easy-to-use fittings.
Copper Pipe vs. PEX Pipe
Copper pipe and fittings are in millions of homes and are still used today. Even with the advent of PEX, many professional plumbers still prefer to use copper pipe. About two-thirds more expensive than PEX, copper pipe is readily available at all home improvement and hardware stores. Copper's higher cost is mainly due to the price of bulk copper.
One of copper pipe's strong points is its predictability. Since copper pipe has been so widely used for so long, its durability and lifespan—plus its propensity for developing pinhole leaks—are known quantities.
PEX is the shortened name for cross-linked polyethylene, a super-strong, semi-rigid plastic tubing. For convenience, PEX comes in red for hot, blue for cold, and white for any temperature. These colors are only to aid in installing the product and in subsequent repairs; they do not confer any temperature-related qualities on the pipe.
PEX pipe can make tight bends without being heated. It can handle high pressure and high temperature. One form of fitting is as simple to use as pressing the pipe into the fitting. Another type of fitting is more difficult but not nearly as difficult as sweating joints onto copper pipe. This second method uses copper rings crimped over the pipe and the fitting with a special tool.
How Copper and PEX Fittings Work
Push-fit or stab-in plumbing fittings are a popular type of PEX and copper fitting; SharkBite, John Guest, and Bluefin are popular brand names of push-fit fittings.
With a bit of effort, the pipe pushes into the fitting and is held in place by tiny teeth. Push-fit fittings are the only connector that work either with copper pipe or PEX pipe, so they are capable of joining copper and PEX.
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Watch Now: How to Replace Copper Pipe With PEX
Copper Pipe Basics
- Recycled: About half of the copper used in the United States—which would include plumbing pipe and fittings—is created from recycled copper, according to the copper industry's trade group, Copper Development Association, Inc. (CDA).
- More rigid: PEX's flexibility is great when you want to go around corners but bad when you need to stub out to a toilet or sink. For that, you need to either use a copper stub-out or buy special PEX fittings for his purpose.
- More heat resistant: PEX is heat resistant and can even be used for under-floor radiant heating. But to connect to high-heat services, like your water heater, you need to make that final run with copper or special stainless steel braided connectors.
- Will not give off toxic fumes: As CDA points out, PEX is plastic and will melt and emanate toxic fumes in the event of a fire. Copper has a far higher melt point and does not give off toxic fumes.
- Cheaper fittings: If you do decide to use copper fittings, they are cheaper than push-fit fittings. For example, a half-inch copper pressure tee will cost about ten times less than a comparable SharkBite brand tee.
- Value of copper: The copper pipe that results from a demolition project can be sold because the material is typically valuable enough. This cannot be said for most building materials stripped from home and certainly not for PEX pipe.
PEX Pipe Basics
- Easy to join: With PEX, you do not need to learn how to sweat joints. In just a few minutes, you can learn how to use the system. Or you can purchase a crimping tool that uses either copper or steel rings that tighten the PEX onto brass fittings.
- Easy to cut: While copper is easy to cut with a rotating tubing cutter, PEX is even easier. A razor blade-equipped rotational cutter makes quick work of PEX in just a few turns. Or, even easier, you can cut it with a scissors-type of cutter.
- Low cost: PEX is substantially cheaper than copper pipe.
- Bendable: Half-inch diameter PEX can make 5-inch radius turns without the application of heat. On straight runs, it has a moderate amount of wiggle room without radius supports.
- More expensive fittings: No PEX fittings are as cheap as copper fittings. Push-fit fittings are far more expensive than copper. But even using barbed brass fittings for your PEX is still more expensive than copper—about three times more expensive.
Recommended for DIY: PEX Over Copper
Do-it-yourself home remodelers may wish to use PEX pipe over copper for most of their plumbing work. PEX is easy to work with and has almost no learning curve. Just be sure to check your local codes to see if PEX is approved for use in your municipality.
With copper, amateurs will find joints difficult to solder. Given the fact that most copper pipe corrosion occurs near joints, this is not an aspect of your plumbing that you want to get wrong. PEX joints are nearly foolproof.
Push-Fit vs. Crimp/Clamp PEX Connectors
No tools required
Easy removal with inexpensive device
PEX crimping tool required
Difficult to remove: snap off ring
PEX over copper is, for many amateur plumbers, a foregone conclusion. But the more difficult question is whether you should use push-fit connectors or crimp/clamp connectors.
Throughout a large plumbing project, such as whole-house plumbing replacement, barbed crimp/clamp connectors will save you considerable money, even after taking into account the initial investment in a crimp/clamp tool.
If your working space is tight, push-fit fittings can be easier to attach than crimped or clamped barb connections, due to the space needed to operate the tool. As long as you have space to the side, you should be able to fit the tool.
But in other tight places, the crimp/clamp connectors can actually be easier to install than push-fit connectors. These are places where it's difficult to fit your hands to make that quick, decisive push necessary for a tight connection.
If you are nervous about making tight connections, push-fit fittings will help—but they are not necessarily foolproof. Getting the PEX or copper stabbed into the fitting can be difficult. Surprisingly, PEX can be harder to stab in and remove than copper.
How to Create Tight Push-Fit PEX Joints
Cut the PEX or Copper Pipe
Cut the end of the pipe square (90-degree angle). Use a pipe cutter to produce a true cut. A hacksaw or reciprocating saw will not work as well as these inexpensive cutting devices.
De-Burr the Pipe
Use the wire-bristled brush to de-burr the cut, if copper pipe. PEX usually cuts cleanly but it's always a good idea to examine the end and remove any loose shreds with a utility knife.
Mark Pipe Depth
The trick to ensuring a tight, long-lasting joint for push-fit fittings on either copper or PEX pipe is to mark the intended depth on the pipe with an indelible marker. Insertion depth may vary by brand.
Place the end of the pipe at the end of the push-fit fitting. Make sure that the pipe moves straight into the fitting, not at an angle. Then, in one decisive move, push the pipe into the fitting. If you hesitate, the pipe may only partially insert into the fitting.
Check the Depth
Check to make sure that the pipe has reached the correct depth. It must meet the marked line.
Remove the Fitting If Necessary
If the pipe is incorrectly fitted, remove it and fit it again. Place the semi-circular removal tool over the pipe. Hold the fitting with one hand. Hold the removal tool with two fingers of the other hand and slide it down toward the push-fitting. Maintaining this pressure, separate the fitting from the pipe.
Why Copper. Copper Development Association, 2021.