A blower assembly includes a blower housing and a fan wheel mounted within the blower housing and being rotatable about an axis of rotation. The fan wheel includes a support disk positioned near a center of the fan wheel. A first wheel portion having a first plurality of impeller blades is positioned adjacent a first side of the support disk. A second wheel portion having a second plurality of impeller blades is positioned adjacent a second side of the support disk. The first wheel portion and the second wheel portion are asymmetrical about a plane oriented perpendicular to the axis of rotation and intersecting the support disk.