I have not seen anything for the typhoon thats states that, You would think that there is water that would be trapped in it and not be able to dry out, and even if for some reason it did it should not hurt the unit, it's dry when we get them, the only thing that they say on the typhoon is that if it sets for a few days or longer run it for a few minutes before saving the water, maybe from setting up there may be a chance of some TDS build up I'm guessing.