Honeywell recommends replacing the filter every 30 to 60 days, depending on the quality of water used and how frequently you use the humidifier. You should also replace the filter if it is hard, crusty, brittle, develops an odor, or if the humidifier’s moisture output has decreased. If you live in an area with hard… Continue reading Honeywell TrueSTEAM HM512 Series Steam Humidifier Steam Humidifiers Humidifiers