REBEL there are two different types of pipes when using for water lines that you normally find in housing one is COPPER and the second is CPVC....which is more yellow and stronger then pvc...pvc will break super easy with freezing water...when you redo them all you have to do is put in new cpvc lines...add some heat tape to the areas where it could freeze and place the black foam around it...and it wont freeze...we had minus 37 here and the lines were fine...hope this helps...there is new water lines that are plastic red/blue you can find in stores but i believe those are expensive as well....hope you get it all figured out...
edited to add...plastic shouldnt be melted together...they are put together using the purple priming glue and then the orange cement glue
On that note , they have quick couplers now as well , done correctly no glue required etc . I believe the original intent with the CPVC is to allow curved and easier placement as well as cost , prices of copper has skyrocketed in recent years , also you don't get that rattle like some houses did when the improperly installed copper pipes touched the studs etc