A window covering auxiliary device includes at least one attracted member, an operation handle and at least one attracting member. The at least one attracted member is mounted on a window covering. The operation handle includes a holding unit and a guiding unit. The guiding unit is mounted on the holding unit and has a top provided with a guide portion which is provided with a receiving recess. The at least one attracting member is mounted in the receiving recess of the operation handle. The at least one attracting member and the at least one attracted member are magnetically attracted with each other.

A novel and useful frameless supplemental window for fenestration incorporating infiltration blockers suitable for use with existing windows. The supplemental window, in one embodiment, comprises plastic sheet material with bullnose edging around it. Corner braces add rigidity and strength to corners in several embodiments. An attachment mechanism secured either to the sheet material or the bullnose edge functions to fasten and/or seal the supplemental window to an existing window. Infiltration blockers fastened to the sheet or bullnose prevent or minimize air leakage around various window elements. The bullnose edging and infiltration blockers function to substantially enclose (i.e. trap) a volume of air between the window pane and the plastic sheet material. The supplemental window is configured such that the layer of air enclosed is of an optimum thickness within a preferred range of 0.15 to 0.75 inches to maximize thermal insulation properties of the supplemental window.

A roll of energy-efficient laminate substrate is described. The energy-efficient fenestration assembly includes: (1) a performance film having at least one energy-efficient property; (2) a supporting film mechanically supporting said performance film; and (3) wherein said performance film is laminated and rolled with said supporting film to form said roll of said laminate energy-efficient substrate.