A blower for a high efficiency furnace is provided with an increased interior space for accommodating an impeller of maximum practicable diameter. The blower includes a blower motor and a blower housing having a bottom piece and a top piece assembling with the bottom piece to define an interior of the blower housing. The top piece includes an annular lower support portion for supporting the blower motor and an annular upper portion extending above and around the lower portion. The upper portion has an outer peripheral edge and lugs extending outward beyond the outer peripheral edge. The lugs have lug holes to receive mechanical fasteners to secure the blower housing to an external device. The head of the mechanical fasteners are positioned above the lugs on the upper portion of the top piece. In this arrangement the diameter of the bottom piece is not limited by a need to accommodate spacing for the head of the mechanical fastener. Additionally, the top piece and bottom piece have interlocking internal seals that provide positive engagement when the blower housing is assembled.