They are ridiculously expensive, and cover almost nothing. I tried 1 set (2 small freon tank size cans) wanted to insulate a small 8x16 room. That size setup did 1 - 8x8 wall not even 2".
  Would have cost over $2K  to insulate that room, $2800 if I also did the ceiling.  Went and got 6" fiberglass bats and did the entire room for less than $400.00.


OH, yeah, the chemical reaction makes A LOT of heat