I own an old cottage, probably 40 years old or more. The pipes are not insulated, they were drained for the winter months, but we did not make it through the rough NH winter. I have many leaks in my pipes at the elbows. I am replacing the elbows, and resealing, but was told by others that I might want to switch to PVC because it does not expand and contract in the cold. Is this true? I have well water, does that hurt cooper pipes? Pvc pipes? HELP!