Window blankets are a very effective way to improve heat retention by keeping out drafts. They can also be used to reduce heat coming into a window. They can be made quickly with whatever materials are available.
Measure the width of your window including the frame. Add a 10 cm hem for edges. Also add an extra 5 cm for whatever way you are going to attach them to the top of the window/door.
You will also need Velcro tape the width of the window and some thick ties.
You will need a front cover, some material for inside – this can be old blankets, fleece material or any other thick material, and then the insulated backing material.
The interlining should measure the width and the height of the window + frame. Place on back of front material, turn a 10 cm hem and sew around the 2 sides and the bottom. (this can be hand sewn with locking-in stitch if you don’t want the stitching to show).
The backing material be the same size as the front material. Turn the 10 cm around the sides and the bottom and sew.
Place the front of the curtain facing down (interling should be showing). Now place the lining on top (hems inside) and match the tops and side. Turn the top over by 10 cm. If you are adding velcro, pin this in place and sew the edges of the velco. This will hold all the layers in place. You can sew the edge down.