I live here in New England and have a Hydro Air system with a boiler sending hot water to an air exchanger. The PEX pipes that go to the unit for the second floor run partially through an unheated attic space. Should they be insulated?

Thanks

PEX may stand freezing better than any rigid pipe, but it is still going to lose heat. I have no figures to back my opinion, but surely as cheap as the readily available pipe insulation is, you would be ahead. Some of it even has stickum to seal the seam now.

It would also cut the heat in the attic, important to avoid the dreaded ice dams.