I feel it does. Yes. Im a big guy 250lbs so create alot of body heat but I remain very comfortable. I wish I would have bought this years ago. I absolutely love this mattress.
I think we both got duds. Mine did the same thing. 12" on ends and10" in middle. Not 14" that's 4 sure!!! And was really too hot to sleep comfortably on. Saved myself a headache and purchased a 4" sorta gel topper. Now I can sleep better.
It is recommended by the manufacturer to have a bed frame with slats that have no more than a 2 or 3 inch gap. This allows the mattress to breathe and prevents moisture from getting trapped. This also prevents the mattress from sinking down into those large gaps. I wouldn't recommend using this with a box spring or a large piece of plywood as your base. Stick with slats.
Not recyclable. I took it to the recycling center and they said it was considered garbage. So, because it was so large, I repurposed it and used it to wrap my sleeping bags in and placed them in the attic.
It depends on the frame. If you have a flare bottom like wood or metal then no box springs. If the are gaps underneath where the mattress then yes. Simply put, as long as the bottom of the mattress is laying on a flat and hard surface then no box springs necessary. A mattress warranty will be voided if used in conjunction with a frame that has gaps that are more than 3 inches apart.