How To Blackout Fake Dormer Windows . Hip dormers can cost anywhere from $4,000 up to $15,000 depending on what it's being used for and the size of the dormer. The silver part faces towards the dormer window offering protection against uv rays while the cordless look keeps your room to be free of clutter.in terms of ease of use, the spring system opens and closes the shades. Why False Dormer Windows are Like Botched Nose Jobs Home Stratosphere from www.homestratosphere.com Observe this happy set of dormer windows: The house would look so much better without them. Like all indow inserts, no destructive hardware is required to mount our blackout window inserts.