Thanks for all the replies.
I will try to cover the sides and top with some foam board and see what I get out of it. The temp i am talking about is really air temp, not "the actual cold side" sorry, and it's steady at 69/70 and that is what I was trying to get up. My bp has never used the cold side!! I guess she likes the warm side, so I don't worry too much about the ground temp on the cold side, but it does sit around 75-80F. Hot side is always at a steady 92/93 ground temp.