picked this up to try to help out the dry air in our house and as soon as i plugged it in after i filled it up it started putting a mist into the air, there was no wait at all, and it is not a steaming hot mist it is just as cold as the water is when you put it in which i do like,works very good, only thing i would say about it is make sure you put it away from the walls and or away from any electronics as it does shoot a mist into the air a pretty good ways away from the unit, i would recommend this to anyone looking to add a little h20 into their air!