ABSTRACT OF THE DISCLOSURE A HVAC module (100) is provided having a non-load bearing module housing defined by a preformed sheet (110) of material folded onto an internal support structure (200). The internal support structure (200) includes a first heat exchanger (210), a second heat exchanger (212), and at least one rigid cross-member (216) interconnecting the heat exchangers (210, 212). An air valve module (214) may be fixably connected to both the heat exchangers (210, 212) for increased torsional rigidity of the internal support structure (200). The preformed sheet (110) of material includes a plurality of contoured panels (112) configured in a predetermined pattern , wherein the contoured panels (112) are folded along adjacent edges (136) and cooperate with the internal support structure (200) to define the module housing having an inlet, an outlet, air passageways, and mixing chambers. The internal support structure (200) may include indexing features to locate and fix the contoured panels (112) of the preformed sheet (110) into predetermined positions.