Having read all the previous reviews on this humidifier I decided to disregard the comments about disturbing sounds from the humidifier. I am sorry I did. The tank construction is so flimsy that when water is released into the wick tank (more than once an hour (depends on the amount of humidification)a very LOUD knocking sound (5-7 bangs at a time)will disturb your sleep. I thought the next door neighbor was doing construction next door, I couldnt believe this was actually coming from the humidifier. Seriously, I was only one step away from going over there and waking them up at 230 am. I wish I had bought the ultrasonic types. If you have hard water..prepare to clean the wicks often as they absorb them, discolor and turn hard. I can't complain about the basic function..the unit humidifies well but even after almost a month I cannot get used to hearing the banging sounds.