I live in the mountains at 6500 feet and the air is dry and cold, exactly the climate that viruses thrive in - which I found out later after getting a very bad flu, probably the corona variety. I was using the CVS steam vaporizer and it's a real pain to get the steam exactly right and refilling it. So I purchased this unit because of all the good reviews. I plugged this unit in this morning and it instantly output cold vapor. Then I set it to the hot steam setting and after a while it began outputting warm vapor. The unit stops steaming when the humidity rises to the set level. The whole room feels nice and humidified now, no danger of flu this season. I had no idea that the technology had gotten so advanced. By the way, I found that if I add 1/2 tsp of vitamin C powder to my drinking water bottle, my electric kettle does not build up scale, so I'm trying the same thing with this unit. It may prevent having to clean the unit to eliminate scale buildup.