http://huperoptikusa.com/residential...m/residential/

I had it installed by SG in 2012 on my 2 front bedroom(den) windows that face South. I'm sure it helps somewhat but I can still feel the heat through the window and this room is warmer than the rest of the house. I think the sun is just too intense here. Maybe if it was taken off the windows and it got extremely hot, I could then say "Oh, I guess it was helping." It does provide some shading. I hope other people who had this brand(not 3M) applied will reply.