Entry Door Window, how do I get privacy at night?

Poppy & Nana wrote:
Trim a piece of vinyl and add Velcro to strategic places - remove when not needed...

I did this, but with Reflectix type material (I cut a cheap windshield cover to fit). One thing that I've noticed, though, is that the adhesive on the Velcro fails after being in high heat conditions when facing the sun. Maybe there is a high heat Velcro option?