Abstract: A new variable burner orifice furnace manifold for reducing the amount of heating fuel used without reducing the heating ability of the furnace. The inventive device includes a manifold pipe with a plurality of spaced apart gas exit openings between its open supply end and its closed end. The gas exit openings are inserted into the burner assembly of a furnace and the supply end is attached to an external heating fuel supply. A valve permitting selective opening and closing is included on the manifold pipe. The valve is positioned on the manifold pipe so that no more than half the total number of gas exit openings are positioned between the valve and the manifold pipe closed end. When the valve is closed, gas flow through the gas exit openings between the valve and the closed end is shut off while gas flow through the gas exit openings between the valve and the open supply end is unaffected.