Can anyone give me a good suggestion on how to make black out curtains that won't heat up a room that is already a hot room to begin with? About how much fabric would I need for each panel? I was thinking about 3 yds, but I don't have a tape measure to get the length of the window. Also, any creative ideas on how to tie them back, should I just use those 3M removable hook things and just have ties for them?