Everything You Need to Know About PEX Pipe

Lauren Murphy
Written by Lauren Murphy
Updated July 1, 2021
Pex plastic water supply plumbing pipe in wall of house
JJ Gouin / iStock / Getty Images Plus via Getty Images

PEX pipes make it easy for plumbing novices to DIY their whole system

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Plumbers and DIYers alike prefer using PEX over traditional copper and galvanized steel pipes because it’s reliable, lightweight, and relatively easy to work with. All of this means PEX pipe allows even the inexperienced DIYer to retrofit their plumbing system; no pro needed.

PEX Pipe Characteristics

If you’ve ever taken a look at your plumbing system and seen a jumble of colorful pipes, you’ve seen PEX pipes. They come in red, white, blue, and gray, and each color is used differently. Red PEX pipes carry hot water, blue pipes carry cold water, and white and gray can be used for either temperature.

PEX can stand up to both hot and cold temperatures, which is why plumbers now use it in water systems for both residential and business properties. But while it’s temperature-resistant, PEX can be damaged in sunlight. Only install it underground (it’s a popular choice for heated floors) or indoors. 

PEX is flexible, too—it will spring back into its original shape if you bend or twist it, making fitting pipes together easy. The pipes come in a variety of lengths, so you can always find what you need for both small repairs and a complete plumbing system overhaul.

The Pros and Cons of PEX Pipes

There are plenty of reasons why DIYers love working with PEX pipes, including their flexibility. However, there are a few drawbacks to consider.

Pros

  • Quiet

  • Inexpensive

  • Color-coded

  • No soldering needed

  • Resistant to corrosion

With PEX pipes, you won’t have to worry about the spooky creaks that metal pipes make. Water flows through PEX without a peep. 

As mentioned earlier, PEX pipes make DIYing a plumbing system totally accessible. This is because they’re fairly inexpensive—PEX pipes are typically one-third the cost of copper pipes—and their color-coding system makes it easy to know which pipe goes where. You also won’t need to solder to put them together, so don’t worry about purchasing a soldering iron. 

Unlike metal pipes, corrosion isn’t a concern with PEX. As corrosion can lead to leaks down the road, that means PEX pipes are a durable plumbing solution. They will last an average of 50 years.

Cons

  • Not recyclable

  • Not suitable for outdoor use

Green-minded DIYers beware: PEX isn’t recyclable. The material doesn’t melt like other plastics do, which poses a major recycling challenge. But it can partially make up for that with its long lifespan.

PEX also isn’t suitable for outdoor use, as exposure to sunlight can damage it. Ultraviolet rays cause the material to break down quickly. If you accidentally leave PEX outdoors ahead of a plumbing project, you’ll end up with dried and cracked tubes in a month or two.

How to Use PEX in Your Home

PEX is a unique and easy-to-work-with material that has multiple uses. DIYers should consider using it for all home plumbing projects as well as for radiant heat flooring.

Plumbing

Leaky pipe? With PEX, you may be able to fix that problem without calling in a pro. But if you’re new to DIY or plumbing, hire a local plumber to do the job. If they use PEX pipes to fix the leak, keep a sharp eye on how they work with it. Then, you’ll feel more comfortable DIYing it next time.

PEX is a uniquely flexible material. It can wind through walls and floors easily. You can even use a single length of PEX for each hot and cold water supply fixture. This tactic that eliminates the risk of leaks at connection points is often called “home run plumbing.” With traditional metal pipes, it wouldn’t be possible.

If your home already has metal pipes, you can slowly splice in PEX whenever a pipe needs to be fixed. And if you’re building your plumbing system from scratch, use PEX pipes throughout it to make the system simpler.

Radiant Heat Flooring

If you’re tired of freezing your bare feet on the bathroom tile every morning, consider DIYing your own radiant heated flooring with PEX. Hello, toasty toes.

In hydronic systems, PEX tubing embedded in flooring distributes hot water throughout the floor and radiates heat. Experts say radiant floor heating is one of the best ways to heat up any space. 

Use specially grooved plywood or foam panels to install the heated flooring. Fit your PEX tubing in the grooves and snake the tubing throughout the panel. Place it where you want your flooring to be, pour over a mixture of sand and cement, and then add your bathroom tile.

How to Connect PEX Pipes

There are several ways to connect PEX pipes, with push-fit being the easiest.

Crimp

With this connection method, copper or brass rings enclose the end of two pipes to secure them together. Use a special PEX crimping tool to secure each one into place. This is one of the most common ways to connect PEX pipes.

Expansion

You’ll need a special PEX expander tool (essentially a heat gun) to use the expansion method to connect PEX. Use the tool to heat and stretch the diameter of the tube, then insert the end of a fitting. As it cools, the tube will contract and shrink down to its original size to create a seal around the fitting.

Push-Fit

This is the easiest (and quickest) way to connect PEX pipes, so it's a popular practice among DIYers. While you won’t need to purchase tools, you’ll want to make sure you get push-fit specified PEX pipes in order for this to work. Push the PEX into a fitting by hand. Small teeth on the inside of the fitting will hold it into place.

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