So here is a good one... went into my local stove shop to purchase new thermometers for the stove top and my doublewall pipe. To date i only use a stove top unit and nothing on the stack. To my suprise, i was advised that having any type of thermo's was not needed! It is kinda like a waste of money! Am i missing something here? How do you know what your stove is doing, maybe people around here cannot read them? I dont know. Guess ill go to lowes!