Does PEX Freeze? How to Deal With Frozen PEX Pipes

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Cross-linked polyethylene (PEX) piping has advantages over other piping options like copper, polyvinyl chloride (PVC), and chlorinated polyvinyl chloride (CPVC) in colder weather because it has flexibility. But although PEX can’t freeze, the water inside PEX piping can. Freezing can begin when the temperature dips to 32 degrees Fahrenheit, while research from the Building Research Council at the University of Illinois deemed 20 degrees Fahrenheit as a temperature alert threshold for uninsulated pipes running through an uninsulated space. More than likely if you have PEX piping, it’ll be in an insulated space, but the water can still freeze in some scenarios. Learn how to unfreeze water pipes here.

How Does PEX Work?

PEX piping is a flexible tubing that cross-links common plastic through radiation. PEX piping gained popularity for radiant floor heating because of its flexibility, but it has started to appear in more homes for water supply systems.

PEX technology has improved since the early days of PEX, where high chlorine levels could cause it to deteriorate slightly. Manufacturers have also added antioxidants to allow PEX to carry drinking water. PEX piping fittings have also improved so few leaks occur.

How to Tell If PEX Is Frozen

PEX isn’t likely to burst if there’s frozen water in the line, but there are some signs to tell if the line is frozen. Some of the signs of a frozen line include the following:

Low water flow: If you notice a drop in your water flow or lower water pressure, it could signal frozen water in the line. A chunk of frozen water could block the water flow and lead to low water flow. Water could still come through the line, though at a trickle.
Frost on the pipe: If frost appears on PEX piping, it can mean the line has frozen inside.
Leaks: PEX piping is less likely to burst than other piping options like copper, but frozen water can damage joints and lead to leaks. If any leaks appear near joints, you might have a frozen line.

What Temperature Does PEX Freeze At?

PEX can start to encounter freezing issues at 20 degrees Fahrenheit if it’s in an uninsulated area. Whether the water in the line freezes will depend on how long the line has experienced temperatures of 32 degrees Fahrenheit or lower, plus the insulation level of that space. Few spaces have piping in uninsulated spaces, so prolonged exposure to cold temperatures is more of a concern than brief periods.

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How to Prevent PEX From Freezing

Preventing frozen pipes helps you avoid having to pay the cost to replumb a home or the cost to repair a burst pipe. PEX will expand and contract to its original shape, but frequent expansion and contraction can lead to PEX losing its strength and shape. You can do a few things to prevent PEX piping from freezing, including the following:

Keep the room temperature above 55 degrees Fahrenheit to prevent the possibility of temperatures dipping below 32 degrees Fahrenheit and water from freezing in pipes.
Use electrical heat tape on the pipe exterior to keep water above freezing temperatures to prevent blockages.
Maintain proper insulation in cold areas like garages, attics, and basements.
Clear outside pipes by turning off the water and opening the spigot to remove any lingering water before closing the spigot for winter.
Use frost-free sillcocks or a hose bib to prevent your pipes from freezing because the stem washer and seat valve remain inside your home to stay warmer.
Use a water monitor to alert you when temperatures in a room dip to potentially dangerous levels. Many home security systems feature apps that can monitor water issues and temperatures.
Insulate pipes. Foam or another flexible insulation material can work best for PEX since PEX can expand and contract.
Turn your faucets on to maintain a slow drip in extremely cold weather, which can keep water flowing and prevent pressure from building up in the pipes if water begins to freeze. Don’t run hot water since it can freeze quicker than cold water.
Winterize your home to seal any cracks or spaces where cold air can infiltrate. It can also mean checking your furnace and doing any maintenance before winter arrives.

How to Fix Frozen PEX at a Crimp

Frozen water in a PEX piping can have noticeable effects at crimps and lead to leaks. Frozen water inside PEX piping can cause it to expand and, once unfrozen, cause it to contract. That expansion and contraction can make it improperly fit at connections and lead to leaks.

If you experience leaking at a connection, begin the fix by turning off your water main. If you have a loose crimp, you might be able to fix it with a PEX crimping tool. If the crimp is damaged, you can remove it and replace it with a new crimp-style adapter at the end of the PEX pipe to stop the leak. If you’re unfamiliar with PEX plumbing repair, contact a local plumbing repair pro.

Advantages of PEX in the Winter

PEX has several advantages during winter when the possibility of bursting pipes increases. It has characteristics that make it more resilient than metal piping. Plus, other PEX properties allow it to keep its strength during cold weather.

PEX is flexible and less likely to burst than rigid piping. It can expand to handle the pressure buildup that frozen water can cause.
Its strength won’t change in cold weather, except in extremely cold temperatures.
PEX is freeze-resistant, which means it’s less likely to burst than copper piping.
It has fewer connections than other piping, which means fewer spots that can spring leaks.
PEX doesn’t corrode and can last up to 100 years.

PEX Pros and Cons

PEX has advantages over traditional piping material because of its flexibility. However, its construction does bring disadvantages. A majority of homes now feature PEX plumbing, and you can identify it by its distinctive red and blue colors. The red piping passes hot water, while the blue piping has cold water flow through it.

Pros:

The flexibility of PEX makes it easy to install and route through homes.
PEX doesn’t require any soldering of joints and doesn’t have galvanized steel.
Water can flow quietly through PEX, unlike copper pipes, which can have knocking noises.
PEX can connect to existing metal lines with proper fittings.

Cons:

PEX requires special tools like crimping tools for connections.
PEX can’t be installed in high heat areas because it can expand.
PEX is sensitive to UV light, which can cause it to break down and make it unsuitable for outdoor use.
PEX can’t be recycled because it doesn’t melt like other plastics can.

FAQs

What is PEX pipe?

PEX piping stands for cross-linked polyethylene and has risen in popularity because of its versatility. PEX has flexibility that other piping options like copper can’t have. That flexibility can help prevent pipes from bursting and causing damage.

How do you unfreeze PEX pipes?

You can unfreeze PEX pipes by following the steps below:

Shut off your main water supply and run connected faucets until they empty.
Raise the temperature by doing any of the following. Turn the thermostat up to warm the pipes and melt any ice blockage.
Dampen towels with hot water and place them on the pipes to help them thaw.
Use a hair dryer or space heater from a safe distance to not melt the pipes.
Use electrical tape on the pipe to melt the ice inside. It can also prevent future freezing by keeping the piping above freezing.

How do I know if my PEX pipe is frozen?

One of the first signs you have frozen water in your PEX piping is a slow water flow. An ice blockage slows down the water flow and creates pressure. That pressure buildup can lead metal pipes to burst. PEX can expand to prevent bursting, but frozen water still needs to be melted. Other signs include leaks at connections and frost on PEX piping.