"White plastic" sounds like irrigation pipe. Not suitable for hydronic heating. Sounds very hillbilly to me.

Maybe it's white PEX? It could have been less labor to do it that way. Salvage value of copper is only worth it when you cut it out and don't replace.

Plumber didn't ask me but I will ask him. There really was no reason I can think of to replace all the copper pipe. I can understand the connections to the old one were down one foot from the original placement, so I would have thought just replace that one foot with the plastic, and leave the rest of the copper pipe alone.

Many plumbers are switching to PEX because it is usually faster to install than a copper replacement pipe. PEX works just as well, is more resistent to freeze damage, and there are tradeoffs in durability (pinhole leaks with old copper vs. rodent or physical damage to PEX). However, he should have made it clear before he did the work.

Bruce

The greedy plumber will make $5 to $10 bucks off that cooper! Or you could have paid him a $150 more to change the copper to fit you smaller baseboard, time is money in any trade so do the math. I wonder why you didn't tell him to leave the copper so you could have scraped it yourself if you're so worried about it. Cooper pipe does wear out, it gets thinner inside as the water moving through the pipe eroding the metal, so he did you a favor replacing those wore out pieces with PEX if it was PEX. 45 year old copper now will plague you with leaks as you and the cooper age, it's a given.

If it was rigid pipe, it was probably CPVC. Very common in new construction and renovations. Why don't you ask the guy and get it from the horse's mouth?