CPVP is the lease expensive way to go. Plex isn't all that expensive
until you start adding fittings. When I relocated our water heater
from under the stairs to our utility room I used cpvc. Copper would
have cost a fortune. The thing I noticed was that even thoug the
water heater was farther away hot water hit the faucets faster. I am
sure it is because it didn't have to heat up the copper along the way
every time a faucet was turned on. I would reccomend doing the whole
bathroom in CPVC. Do NOT do hot in CPVC and cold in PVC. It is not
worthe the headaches to mix the two.