A method of forming an energy exchange assembly may include forming a plurality of creases and a plurality of slits in a membrane sheet according to a predefined pattern, positioning a first spacer on top of a first forming area of the membrane sheet, folding the membrane sheet over a top of the first spacer so that a second forming area is positioned over the top of the first spacer, sealing a first portion of the first forming area to a first outer lateral wall of the first spacer, and positioning a second spacer on top of the second forming area, thereby stacking the second spacer over the first spacer.