Copper vs. Pex in the Cold

The last two days have been an interesting study in the relative merits of copper water line vs. Pex water line (with brass Sharkbite connectors). In yesterday's blog, I discussed how a mistake on my part resulted in a frozen waterline in one of my apartment buildings. Today, I would like to discuss another apartment that had a frozen waterline today and the starkly different result in that unit with Pex vs. the one yesterday with copper.

As you may recall from yesterday's blog post, I failed to ensure that the electric service was on at a vacant apartment and the result was frozen water lines in the apartment at the back of the building. Once I thawed the water lines, there were so many breaks in the water lines that it was a virtual downpour in the apartment. Those broken water lines were all copper. I replaced enough of those broken lines last night to re-establish water service to the two occupied units in that 3-unit building. Since the electric was obviously still out last night at the back apartment, I asked the tenant in one of the other units to let the water drip overnight to prevent re-freezing.

As you have probably already surmised, the tenant did NOT keep the water dripping overnight and the water lines refroze. So, this morning, I went over to the apartment to thaw the water lines with my torpedo heater again. Before I even arrived at the building, I received a call from another tenant in one of our duplexes and she also reported that her water was frozen. I was somewhat surprised that this building had a frozen water line as I have owned this building about 3 years and never had a problem before, even when the temperature reached 10 to 20 degrees below zero! Last night's temperature was only about zero, but the wind was blowing quite strongly.

The interesting facet to my situation over the past 2 days is the stark difference between the frozen water lines that were copper and those that were Pex (with brass Sharkbite connectors). In the unit with the copper lines, there were several breaks in the lines. In the unit with the Pex lines, there were absolutely no breaks in the lines. Furthermore, when the Pex lines that I installed last night refroze this morning, there were no breaks in the lines. My conclusion is that Pex performs exactly as advertised - it's won't break even when frozen solid, whereas copper easily breaks when frozen! This is certainly something to consider when deciding what type of water line to install in rentals in cold climates.