Generally, home-run systems use crosslinked polyethylene piping (PEX), which is suitable for hot water use and resistant to temperature extremes, chemical attack, and creep deformation. Because of the flexible piping, home-run systems can be installed more quickly than rigid plumbing systems, with only one fitting at the manifold, one transition fitting at the fixture, and no need for piping tees and elbows. However, fittings and couplings are available for special situations, such as repairing damaged piping or for creating changes in direction that are tighter than the minimum bend radius allowable for the piping.
Home-run systems equalize pressure, and therefore allow several fixtures to be used simultaneously without dramatic changes in pressure or temperature. In addition, PEX piping can be sized 1/8-inch smaller in diameter than piping in a “tree” type conventional piping system for some fixtures. Hence, hot water arrives at fixtures faster, and less hot water is left standing in pipes after a draw (standing water creates energy loss to the surrounding air). PEX piping can reduce heat loss from water in the pipe because it is a better thermal insulator than copper.