Question: is pex and polybutylene the same size?
Answer: There are two common types of plastic piping which are known as PB (Polybutylene) and PEX (Cross-linked Polyethylene). The main difference between PB and PEX is in how the material is created. ... So if you will be pumping water, or the pipes will be exposed to the cold, PEX is a better option than PB.