As temperatures drop, residential pipes are susceptible to freeze damage, leading to water-related losses if the leaking pipe isn’t detected quickly. A home may have several plumbing and water supply pipes that respond differently to freezing temperatures, while insulation can help prevent leaks before they happen.

That’s why we will explain the science behind freezing pipes and test different plumbing pipe materials for their susceptibility to freezing and bursting.

Water Damage from Frozen Pipes is Devastating

As you can guess, water damage is one of the most expensive, frustrating, and even devastating nightmares a homeowner can face.

And it doesn’t just occur in winter. Many of these winter problems occur through early summer. This happens because water damage often remains hidden until well after temperatures have gone back up.

The number of homes damaged yearly by frozen and broken water pipes is second only to hurricanes. About 250,000 homes suffer damage from frozen and burst pipes every year. A big chunk of this damage could be minimized or even avoided if the best pipe for freezing conditions were used in plumbing projects.

Frozen pipes cause about half a billion dollars in water damage yearly in the United States. Using the best pipe for freezing conditions can help alleviate much of the damage.

The Best Pipe for Freezing Conditions

Copper, PEX, and CPVC are the most common piping materials in homes, but each has pros and cons.

We tested these pipe materials: copper with a soldered cap, CPVC with two glued caps, and PEX with glued caps. Each was filled with water and frozen. Air was removed, creating lots of pressure. Then, they were frozen for 24 hours at 10 degrees.

In the test, we discovered that the copper pipe’s fitting was separate from the pipe, which would have caused water damage. PEX had the best result. It is the least likely to burst and flood your home, which is why so many property managers like PEX pipes use it in their plumbing systems.

Copper in Freezing Conditions

Copper is an excellent material for plumbing. However, it has a significant disadvantage: it loses heat quickly. Also, it has a thin wall and is not as flexible as the other materials. These combine to make copper the most prone to bursting in frozen weather.

When water freezes inside a copper pipe, the copper doesn’t expand to accommodate the swelling. Instead, the thin wall bursts or splits open.

Copper pipes with thin walls don’t expand enough to keep the swelling frozen water from placing tremendous pressure on them. Eventually, the pipe bursts, causing water damage from flooding.

CPVC in Freezing Conditions

A CPVC pipe, a plastic pipe, is rigid and has thicker walls than copper. However, it won’t lose heat as quickly, making it a better solution. This plastic pipe is also less rigid than copper. CPVC will expand slightly, minimizing the pressure on the pipe’s walls and keeping it safe from bursting as quickly as copper.

However, both PVC and CPVC (think of them as coming from the same family of plastic pipes) are brittle and will crack at low temperatures. So, while not the worst solution, they are still vulnerable to freezing conditions. Because the CPVC pipe is brittle, it will crack if it endures freezing temperatures for too long.

PEX in Freezing Conditions

PEX pipe is best under cold conditions because it is flexible. PEX can stretch enough to accommodate the water freezing inside it.

PEX can still burst with enough pressure and swelling from frozen water. But it’s usually the fittings (connections) on either end of the PEX pipe that blow off first. So, it is also important to consider the materials used to connect PEX to other parts of the plumbing system.

Here are a couple of tips to keep PEX (or any pipe material) even more resistant to bursting from the cold:

• Wrap insulation around the pipe, especially in places that are more apt to get cold (basements, attics, near outside walls)
• Shut off the water to outdoor faucets as winter approaches (drain them and remove the garden hose as well)

PEX is a non-rigid plastic material that can withstand freezing temperatures longer than copper or PVC/CPVC pipes. The material can stretch further as the water inside it freezes and expands. But even PEX has its limits.

Always Make The Right Choices For Plumbing

No matter which pipes you select for a project, you must find a good plumber. Much of what makes a great plumbing system is how the plumber aligns the pipes together, not only the material used. Similarly, if you’re unaware of what type of pipe is best according to your application, contact the nearest plumber. They are your local and experienced experts and can advise you on the best based on their knowledge and expertise.

If you already have pipping material and freezing conditions concern you, there are preservative steps you can adopt to minimize the chances of bursting the pipes.

• Wrap your pipes with heat tape in attics or crawl spaces, heat cables, or cover them with foam pipe.
• Seal the leaks properly to block the cold air.
• Secure or disconnect the hoses, valves, and faucets outside the house.
• Leave faucets with a running water drip.
• Keep the temperature of the thermostat constant to reduce strain on your furnace.
• Open the cabinets to allow warmer air to reach the pipes.

Final Thought

PEX was the clear winner in our tests. It is the best pipe for freezing conditions. However, the fittings also need to withstand frozen temperatures. PEX isn’t the correct pipe to use in every application. Your home will use several different pipe materials — some are better for drains and sewer lines, while others are better for drinking (potable) water supplies. If you’re not sure which material to use, ask your plumber. Or read some of the resources below that are written to help you with all sorts of winterization and insulation issues.