One aspect of the invention provides a composite refrigeration line set including: a suction line and a return line. One or more of the suction line and the return line are a composite refrigeration line set tube including: an inner plastic tube; a first adhesive layer circumferentially surrounding the inner plastic tube; an aluminum layer circumferentially surrounding the first adhesive layer and coupled to the inner plastic tube via the first adhesive layer; a second adhesive layer circumferentially surrounding the aluminum layer; and an outer plastic layer circumferentially surrounding the aluminum layer coupled to the aluminum layer via the second adhesive layer. The inner plastic tube is polyethylene of raised temperature. The outer plastic tube is polyethylene of raised temperature. The aluminum layer includes an alloy selected from the group consisting of: AL 3004-O, AL 3005-O, and AL 3555-O. The aluminum layer is butt-welded to itself.