A draft
inducer blower for high efficiency furnaces, including a blower housing which facilitates maximum air flow efficiency through the blower housing while having an overall radial dimension which conforms to the
industry standard arrangement of mounting holes on the walls of the furnaces. The blower housing generally includes a housing body and housing cover, the housing body including a plurality of mounting lugs spaced around the housing body through which bolts may be inserted to secure the blower housing to the mounting holes in the wall of a furnace. The housing cover and housing body each define portions of a
volute which extends around the outer periphery of the blower housing from the cutoff region to the exhaust transition of the blower housing. The
volute includes a cross-sectional area which substantially continuously increases in the axial direction of the blower housing from the cutoff region to the exhaust transition. In this manner, the blower housing has a radial dimension which conforms to the
industry standard mounting hole arrangements for furnaces, yet includes a
volute having an increasing cross-sectional area around the blower housing to provide a diffuser section within the blower housing to maximize air flow efficiency. The housing cover is positioned close to the
impeller periphery to prevent recirculation. The housing cover is provided with a conical section and ribbing to minimize
assembly-caused inlet deflection and to optimize air flow.