An air system (12, 108) for a bed, comprising: a layer assembly (14, 38) having a head end, a foot end, and first and second sides, wherein the layer assembly has a head portion near the head end, a foot portion near the foot end, and a middle portion between the head portion and the foot portion, the layer assembly having a spacer layer comprising spacer material configured to allow for air flow through the spacer material, a lower spacer material positioned at the middle portion of the layer assembly under the spacer layer, and a cover comprising a cover top layer and a cover bottom layer, wherein the cover substantially encloses the spacer layer with the cover top layer above the spacer layer and the cover bottom layer below the spacer layer; and a distribution manifold (74, 116) extending through a portion of the cover, wherein the distribution manifold is positioned above the cover bottom layer and under the spacer layer so as to flow air from the distribution manifold to a space under the spacer layer, from the space under the spacer layer into the spacer layer, and from the spacer layer out through the cover top layer, wherein the distribution manifold is thicker and wider than the lower spacer material such that some air from the distribution manifold flows under the lower spacer material, some air from the distribution manifold flows into the lower spacer material, and some air from the distribution manifold flow to the sides of the lower spacer material. a layer assembly (14, 38) having a head end, a foot end, and first and second sides, wherein the layer assembly has a head portion near the head end, a foot portion near the foot end, and a middle portion between the head portion and the foot portion, the layer assembly having a spacer layer comprising spacer material configured to allow for air flow through the spacer material, a lower spacer material positioned at the middle portion of the layer assembly under the spacer layer, and a cover comprising a cover top layer and a cover bottom layer, wherein the cover substantially encloses the spacer layer with the cover top layer above the spacer layer and the cover bottom layer below the spacer layer; and a spacer layer comprising spacer material configured to allow for air flow through the spacer material, a lower spacer material positioned at the middle portion of the layer assembly under the spacer layer, and a cover comprising a cover top layer and a cover bottom layer, wherein the cover substantially encloses the spacer layer with the cover top layer above the spacer layer and the cover bottom layer below the spacer layer; and a distribution manifold (74, 116) extending through a portion of the cover, wherein the distribution manifold is positioned above the cover bottom layer and under the spacer layer so as to flow air from the distribution manifold to a space under the spacer layer, from the space under the spacer layer into the spacer layer, and from the spacer layer out through the cover top layer, wherein the distribution manifold is thicker and wider than the lower spacer material such that some air from the distribution manifold flows under the lower spacer material, some air from the distribution manifold flows into the lower spacer material, and some air from the distribution manifold flow to the sides of the lower spacer material.