Comparing Aquatherm to CPVC? Here's what Green Building Advisor has to say on the matter: #greenbuilding
In many cases HDPE is used underground for natural gas. Aquatherm has a national rep network you can access a local rep by going to http://www.aquathermpipe.com/find-a-local-representative.html . Most if not all of the reps will rent the fusion welder for a reasonable price. Their focus is not on DIY at all right now, but some people have taken the 1/2 day training and become certified to install it. By taking the training, they access a multimillion dollar warranty. Most of their residential applications are in homes where people want high quality potable water and/or a very green, long-lasting piping system.