UTH's make poor primary heaters.
Where UTH's shine is in creating a stable hot spot or "basking" area(when regulated) that allow ectothermic creatures to maintain ideal body temps as need dictates.
I find my snakes in the warm hides shortly after feeding otherwise they are more likely to be found in the cool hide. I don't know if others have this same experience or not but, it demonstrates that sometimes the snake will want to be warmer that others.