An air flow accelerator for creating an air current. The air flow accelerator comprises an air inlet, an air outlet, an impeller, and a motor for rotating the impeller to create an air flow passing from the air inlet to the air outlet. The air outlet comprises a first elongate plenum having an interior passage for receiving the air flow, and a second elongate plenum connected to the first elongate plenum by a common wall between the first elongate plenum and the second elongate plenum. The common wall has a plurality of apertures therein. The second elongate plenum comprises a plurality of chambers such that one or more of the apertures connects to each of the chambers. The second elongate plenum further comprises a narrow slot for emitting the air flow. The air flow emitting from the slot forms a jet inducing a flow of air from outside the air flow accelerator.