Yes, PEX pipes can freeze. While PEX is flexible and generally more resistant to bursting than rigid copper or PVC, the water inside can still freeze when exposed to temperatures below 20°F (-7°C) for extended periods without adequate insulation.
PEX pipes can freeze once the temperature reaches about 20 degrees Fahrenheit. They can expand a finite amount, lowering the overall pressure on the pipe itself. However, the colder it becomes, the more likely your PEX pipes will freeze and burst.
PEX pipes can stretch and flex somewhat, allowing ice to expand without bursting the pipe. However, this doesn't mean PEX pipes are immune to bursting when frozen. PEX piping can still burst if it can't expand evenly due to a concrete slab or compacted soil surrounding it.
In general, PEX would freeze when surrounding temperatures reach 20 degrees Fahrenheit—especially if the water line is uninsulated.
Most pipe types, if they freeze, will often burst in freezing conditions, but SharkBite PEX pipe is more forgiving. PEX is flexible and performs better in freezing conditions than rigid pipes like copper, PVC and CPVC.
However, recent failures and the lawsuits that have followed those failures lead to the idea that PEX plumbing systems aren't as good as once assumed. PEX systems can fail in either the pipe or in the fitting. The most notable failure occurs when the fittings fail and water starts leaking and causing visible damage.
A few tips for preventing frozen PEX pipes:
PEX pipe is more resistant to bursting in freezing conditions than metal piping. Because it's flexible, PEX tubing expands rather than splitting, minimizing costly repairs. A long product lifespan reduces cost associated with it, increases customer satisfaction and lessens waste.
How to Tell if PEX Is Frozen
At 32°F, insulated pipes can freeze in about 12 hours and about six hours between 20 to 32°F. The timeframe for freezing becomes even shorter when your pipes are uninsulated. These are approximate figures, as other factors like wind exposure, pipe material, and water flow can also influence the actual freezing time.
As temps drop, the risk of having frozen pipes in your home increases. Typical high-risk areas for freezing include pipes within exterior walls, as well as exposed pipes that run through unheated or uninsulated areas such as attics or basements.
The time varies based on temperature, insulation, and pipe location. Most accessible frozen pipes thaw within 30 minutes to a few hours using safe methods. Pipes in walls or attics may take longer as the surrounding space warms.
Insulation: Insulating your PEX pipes is crucial to prevent freezing and maintain optimal temperatures. Follow these steps to properly insulate your pipes: Identify any exposed PEX pipes in unheated areas such as basements, crawl spaces, or attics.
Water freezes at 32°F, but pipes usually don't freeze unless the temperature dips to 20°F or lower. As mentioned earlier, pipes in unheated or uninsulated areas are the first to freeze.
Put the PEX in the attic, inboard of the insulation, it'll be fine, there is no need to heat trace it. If you get a really cold snap for an extended period of time, yes the PEX might freeze, but here's the thing - PEX generally does not burst like copper or CPVC.
While we know that water freezes at 32 degrees Fahrenheit, keep in mind that indoor pipes are somewhat protected from the extreme outdoor weather. Without a heat source, pipes may take as little as 3 hours to freeze at 20 degrees Fahrenheit or lower.
When a cold snap hovers around or below 32 degrees Fahrenheit for a couple days in a row it's time to let at least one faucet drip. Pay close attention to water pipes that are in attics, garages, basements or crawl spaces because temperatures in these unheated interior spaces usually mimic outdoor temperatures.
While PEX handles cold better than copper or PVC, freezing temperatures for PEX pipes can still cause problems. Ice forms inside the pipe, expands, and stresses the pipe walls. PEX can stretch and recover, but repeated or prolonged freezes may lead to leaks or splits.
Can You Flush the Toilet If Your Pipes Are Frozen? In most cases, no. Attempting to do so can cause pressure buildup in the pipe and lead to bursting. Additionally, flushing a toilet with a frozen pipe can result in unsanitary conditions due to a lack of proper drainage.
Leaks and Fittings Issues
PEX plumbing uses fittings and connectors that are typically made of plastic or metal. Over time, these fittings can loosen, leading to leaks. Problems can arise with crimp rings, as improper use of a crimping tool can weaken the joints.
The 135 rule means horizontal drain pipes cannot connect using a fitting that creates more than a 135-degree change in direction. In plain terms, you cannot use a standard short-turn 90-degree elbow between two horizontal drain lines. Plumbers use two 45-degree elbows, a long-sweep 90, or a wye-and-eighth-bend instead.
PEX is cheaper than copper, both in terms of material and labor costs. The cost of PEX vs copper is particularly important for large-scale projects, such as commercial repiping, where budget constraints are a key factor. PEX is also easier to install.
You can use a heating strip wrapped around the pipe so long as it has no adhesive material. If you live in an area prone to freezing you should still take precautions to protect your PEX pipe, such as foam wrap.
Allow warm air to circulate in the area where the water comes in to the house. Leave utility room doors open and clear space around the water line to help prevent cold pockets of air near the pipes. Remove contents of vanity cupboards that conceal pipes, and leave the doors open.
No pipe material is 100% freezeproof, but PEX is freeze-resistant. It's designed to expand and contract with temperature changes without immediate damage. You should still encourage customers to keep pipes warm, though. It's a good practice to get into and it's still the best way to avoid winter-related damage.