I purchased this cool mist humidifier for two purposes. One, to help keep the air moist due to our dry conditions in Arizona and two, to help keep the room cooler. It does both very well. I've noticed that my allergy symptoms have diminished and I'm not having to use a ceiling fan all the time. It has worked so well, I'm not even having to water the plants as often. When it's on full throttle, so to speak, it sounds like a regular fan blowing. However, when you put it on the silent mode, it is extremely quiet and you don't notice that it is turned on. Every once in a while you hear a gurgle sound due to the water moving through the system...it isn't very loud. Sounds like you are taking water from a water cooler. The night light is an added bonus. Light enough to sparkle the room with a dim light but not too bright to keep you up at night. This was a fantastic purchase and I would recommend it to anyone.