I would think it would work better on a SS conical than a glass carboy. SS is a better conductor of heat than glass, and also thinner than a glass carboy. Another thing to consider is the size of the conical. A 10+ gallon conical will produce more fermentation heat, due to its overall mass, than a 6.5 gallon carboy. I would think that a conical would be more difficult to cool and easier to heat than a carboy.