PEX polymer is a material obtained by cross linking the carbon atoms using three different methods. These methods result in PEX-a, PEX-b, PEX-c. Even though the same material is obtained by using these manufacturing processes, the difference is in PEX costs. It costs a lot less to fabricate PEX-a and PEX-b than it costs to make PEX-c.
Many times when using PEX tubing people can see that the resistance of this material is not quite as good as it should be. Used in bathrooms PEX has a major disadvantage.
When the cold pipe is placed next to the hot pipe, water will start forming on the cold pipe, and it will eventual fall on the floor. When living in a building, this means that the neighbors living downstairs will get a permanent wed wall from the pipes used above. The problem is usually solved with isolation on top of the polymer pipe. This means additional costs and additional work. If the bathroom has in wall pipes, the walls will have to be removed so that the plumber can reach the pipes.
Even so, PEX supply stores still have a lot of good things to say about the material they are selling. PEX supply companies have an increased demand for this product only because it is much cheaper than traditional metal pipes, and it is a lot easier to install and use, requiring far less fitting tools.
But costs can reach the same amount, when thinking of permanent replacements of the tubes. If the pipes work perfectly for the cold water installations, in hot water these pipes can cause a lot of problems.
What polymer pipes are really good for is electrical cabling. Some cables need to be placed on the exterior walls inside the hose, thus representing a danger to children or even to adults. Polymer tubes can hold the cables together in an isolating layer.
