A heat exchange apparatus having a plurality of plates through which heat is exchanged from a first gas to a second gas is provided with a plurality of plates having first and second opposing patterns. Each of the opposing patterns is provided with a plurality of sinusoidally varying surface strips and a plurality of spacing ridges between the surface strips, whereby the second gas flows in a generally sinusoidal path in a first direction along a first side of the first and second patterns between the first and second plates and the first gas flows in a generally sinusoidal path in a direction opposite the first direction along the other side of the first and second plates. The plurality of spacing ridges on the second pattern are disposed relative to the spacing ridges on the first pattern such that the spacing ridges on the second pattern lie along a line substantially in the middle of the surface strips of the first pattern, and vice versa. The first and second patterns are provided with sealing ridges in abutting relationship, the sealing ridges so disposed to provide an inlet and outlet for the second gas when the plates are mounted in the heat exchange apparatus.