A window unit comprising: an intermediate pane disposed in an interior space defined between first and second panes (110, 120) of the window unit; and a spacer arranged about a perimeter of the first, second, and intermediate panes, the spacer comprising: an outer elongate strip defining (i) a length corresponding to a distance between inner surfaces of the first and second panes, (ii) a first surface, and (iii) a second surface contacting and supporting the intermediate pane; first and second inner elongate strips (150, 151), each defining a first surface and a second surface, the inner elongate strips arranged so that each of the first surfaces of the inner elongate strips are spaced from the second surface of the outer elongate strip towards an interior space of the window unit, the inner elongate strips being spaced from each other to form an elongate intermediate pane gap; a first outer support leg extending between the outer elongate strip and the first inner elongate strip; a second outer support leg extending between the outer elongate strip and the second inner elongate strip; a first inner support leg extending between the outer elongate strip and the first inner elongate strip, the first inner support leg positioned between the two outer support legs; and a second inner support leg extending between the outer elongate strip and the second inner elongate strip, the second inner support leg positioned between the two outer support legs, wherein the outer elongate strip and the first inner elongate strip each extend a first distance from the first outer support leg to the inner surface of the first pane, and wherein the outer elongate strip and the second inner elongate strip each extend a second distance from the second outer support leg to the inner surface of the second pane. an intermediate pane disposed in an interior space defined between first and second panes (110, 120) of the window unit; and a spacer arranged about a perimeter of the first, second, and intermediate panes, the spacer comprising: an outer elongate strip defining (i) a length corresponding to a distance between inner surfaces of the first and second panes, (ii) a first surface, and (iii) a second surface contacting and supporting the intermediate pane; first and second inner elongate strips (150, 151), each defining a first surface and a second surface, the inner elongate strips arranged so that each of the first surfaces of the inner elongate strips are spaced from the second surface of the outer elongate strip towards an interior space of the window unit, the inner elongate strips being spaced from each other to form an elongate intermediate pane gap; a first outer support leg extending between the outer elongate strip and the first inner elongate strip; a second outer support leg extending between the outer elongate strip and the second inner elongate strip; a first inner support leg extending between the outer elongate strip and the first inner elongate strip, the first inner support leg positioned between the two outer support legs; and a second inner support leg extending between the outer elongate strip and the second inner elongate strip, the second inner support leg positioned between the two outer support legs, an outer elongate strip defining (i) a length corresponding to a distance between inner surfaces of the first and second panes, (ii) a first surface, and (iii) a second surface contacting and supporting the intermediate pane; first and second inner elongate strips (150, 151), each defining a first surface and a second surface, the inner elongate strips arranged so that each of the first surfaces of the inner elongate strips are spaced from the second surface of the outer elongate strip towards an interior space of the window unit, the inner elongate strips being spaced from each other to form an elongate intermediate pane gap; a first outer support leg extending between the outer elongate strip and the first inner elongate strip; a second outer support leg extending between the outer elongate strip and the second inner elongate strip; a first inner support leg extending between the outer elongate strip and the first inner elongate strip, the first inner support leg positioned between the two outer support legs; and a second inner support leg extending between the outer elongate strip and the second inner elongate strip, the second inner support leg positioned between the two outer support legs, wherein the outer elongate strip and the first inner elongate strip each extend a first distance from the first outer support leg to the inner surface of the first pane, and wherein the outer elongate strip and the second inner elongate strip each extend a second distance from the second outer support leg to the inner surface of the second pane.