This large room, 4 gallon capacity, humidifier doesn't leave any white dust on furniture like most sonic humidifiers. You will have the continued expense of replacing the "wicks" about every 6 weeks, but they are what filters out the minerals that leave behind the white dust. I wish this model had a thermostate and ran much quieter. If you turn the fan speed down to low it's whisper quiet. I would buy again.