Have you got a window skylight that just gets too hot in the summer and loses all the heat in the winter.  Well we have just installed a roller shutter on a window with these issues.  The large expanse of glass heated the main lounge room up in the summer and heat loss in winter was a factor in being able to kept the lounge room heated.  We have installed a motorised roller shutter with a foam filled internal core.  This motorised roller shutter lowers at the push of a button covering the skylight is a reflective and insulated cover.