well i u have any construction experience i would say buy a few 2x4's and only zip your top bean into the ceeling.then drill studs into the 2x4 u just installed and hang panda film on both sides if u want insulation.keep in mind i u seperate your room your going to want 2 over lap several pieces.just having one piece hanging with velcro or a tarp zip up u will still see the light. i have a sheet of pands film then hung infront of that a black tarp with 2 zippers and a secret door and the light still peers through from time to time

HEADSHAKE! panda film will hold some cool air for a short perriod of time,it is pretty thick i think like 8 or 10 mil if u want keep the cool air in u can also add some verry cheap insulation.u can use r-134 insulation foam.its pretty handy.its sold at home depot in the roofing department.it comes in sturdy sheets u can cut to size.the largest sheet is 3 inches thick and 5x10 but they come in many sizes.i use a 4x8 sheet on my floor in my g/r because the floor is concrete.