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!

PVC will freeze just like the copper did, and it will also split or break the fittings. The only one that I know that will give you a little protection against freezing and splitting is PEX because it will expand somewhat without splitting. But the fittings are still rigid and they will cause trouble in freezing weather.

I agree, PVC will freeze and crack too as will CPVC. PEX not only will flex a hair it is way easier to use when repiping an existing home. It is flexible enough that you can thread it between rafters and up into blind wall cavities with obstructions. Your old pipe blew not because of the harsh NH winter, they blew because they needed to be blown out not just drained or shut off.

I agree, PVC will freeze and crack too as will CPVC. PEX not only will flex a hair it is way easier to use when repiping an existing home. It is flexible enough that you can thread it between rafters and up into blind wall cavities with obstructions. Your old pipe blew not because of the harsh NH winter, they blew because they needed to be blown out not just drained or shut off.

If freezing is a consideration, I would use PEX, which will expand up to 8 times its original diameter when frozen and then return to its original form when thawed.

If possible, I would pull home runs to each fixture (thus eliminating the need for locating fittings in uninsulated spaces) from a centrally located manifold that is positioned in a well insulated location.