Why PEX has an Advantage in the Winter
Its chemical structure allows for higher flexibility and pressure capabilities. And the plastic pipe’s strength doesn’t change in cold weather except in extreme temperatures. So when there’s more pressure, PEX expands, meaning it will survive a high-pressure situation, like water freezing, longer than rigid pipes.
All types of PEX — a, b and c — share nearly the same capabilities too. And SharkBite makes a PEX-b that not only holds up to freezing but is also one of the strongest PEX types on the market.
Freeze Resistant Doesn’t Mean Freezeproof
Just because it can tolerate the cold better than a rigid pipe, that doesn’t mean it won’t freeze or break.
So at what temperature will it freeze? It depends. While pipes themselves don’t freeze, the water inside of them does when the area around the plumbing reaches the freezing point. So even if the temperature outside is at 32 degrees, pipes underground, for instance, may not reach that same temperature unless it’s lower than 32 outside. Each case varies, but the Building Research Council at the University of Illinois defines the “temperature alert threshold” as 20 F for uninsulated pipes, particularly for Southern states that would experience sudden dips in temperatures throughout the winter.
Ways to Keep PEX Pipe from Freezing
PEX pipe will expand if frozen and contract to its original shape when thawed. But putting frequent stress on the system weakens it, increasing chances of failure and leaks. So, to preserve the strength of your pipes, you should use the same standard insulation precautions with PEX to keep it from freezing.
A few tips for preventing frozen PEX pipes:
- Keep the room temperature above 55 F.
- Add insulation to particularly cold places such as attics, garages and basements.
- Drip faucets to keep water moving in the pipes.
- Shut off the water to outside hose bibbs (spigots) & drain the pipes.
- Install frost-free sillcocks.
- Install a water monitor that alerts you when the temperature in a room get to the point where a pipe could freeze.
Source: How PEX Pipe Performs in the Winter