We have had this humidifier for about a year in our kids room. It is usually only ran every night. This last week it has become noticeably louder when operating, but is still producing a good amount of humidity. I believe part of this issue is that our water is a little too hard. We have kept everything clean that we can see, but I believe the issue in in the base. Called customer service today and was told we will be receiving a replacement free of charge.