A heat exchange matrix includes a plurality of generally planar foils including a water retaining material, arranged in spaced, substantially parallel relationship. Each foil defines a main plane having a flow direction and a transverse direction and the foils include strips that extend a strip length in the transverse direction and are separated from each neighboring strip in the flow direction and each strip is offset from the main plane by a distance that is different from that of its neighbor. The matrix may be provided in a flow channel for air to be humidified and cooled.