I've rerun my kitchen plumbing in CPVC. Last year was our coldest in
some time (in the teens) and the old iron pipe with foam insulation gave
me no problems. All this in an unheated basement above which I've
insulated the floor. It's tempered somewhat from out doors, but not much.

Should I expect any more problems out of the CPVC than I had with the
steel?

I've heard that 20 F is the magick number for frozen pipes.
Apparently since there is no nuclei for ice crystal to form around, it
has to supper cool. Not sure how that works for the hot water after it
has left the tank.

Jeff