wall mountable window energy saver 12 of the present invention 10 shown is the assembled window insulation energy saver mounted to a wall over a window opening having window trim 52 around said window jamb 18 providing an insulative air gap once installed by means of a plurality of predrilled apertures 42 and provided screws 40 for mounting the window insulation energy saver to the interior wall 16 surface to prevent air movement and water vapor movement between the interior room and the window unit covered by said window energy saver countersunk apertures 42 are disposed in the frame 20 to receive mounting fasteners 43 for attachment to the wall 16 fig7 is an assembled view of the wall mountable window energy saver 12 of the present invention 10 shown is the assembled window insulation energy saver having the flexible impermeable sheet air and vapor barrier 50 extendable and retractable from a roller housing 56 and secured to the frame 20 with attachable detachable mating fasteners 48 once extended the flexible impermeable sheet air and vapor barrier 50 provides an insulative air gap to prevent air movement and water vapor movement between the interior room and the window unit 26 covered by said window energy saver fig8 is a front exploded view of the window jamb mountable window energy saver frame 14 of the present invention 10 the jamb mountable window insulation energy saver 14 has a frame 20 with a top portion 28 a bottom portion 30 a right side portion 34 and a left side portion 32 the top and bottom ends of the left side portion 32 and the right side portion 34 have threaded recesses 36 and the top and.