Abstract: The invention provides a simple, unobtrusive method of essentially sealing a window to control environmental elements. The method is easily installed, adjusted or removed and can be used behind existing window coverings. The method consists of at least two adjustable tension rods of equal length and a supple application specific fabric. The fabric has a width equal to that of the tension rods when fully extended. The length of the fabric is equal to or greater than the length of the window to be covered. An open-ended hem large enough to encase the tension rods is sewn along the width ends of the fabric. A tension rod is inserted into each of the open-ended hems. The tension rods are adjusted to fit snuggly in the window casing. The upper rod is abutted to the top of the window casing and the lower rod is abutted to the bottom.