White dust in the air flow coming out of the humidifier is a sign of high levels of minerals in the water. Use distilled water to reduce the white dust.
It is not recommended that you operate a humidifier without a filter. Debris, airborne contaminants and minerals from the water can be damage the humidifier or be released into the air in the room.
Humidifiers are used to moisturize surrounding air that can become dry and dust-filled due to indoor heating or low air flow. Many humidifiers have filters that filter out minerals found in water, airborne debris and dust so that the moisturized air coming out of the filter is clean. The average filter lasts between two to three months and should be replaced as needed. Some filters are reusable and cleanable. In either case using a humidifier without a filter is a temporary solution; replace the filter for long-term use.
Turn off the humidifier and unplug the power cord.
Remove the existing filter, if any, from the humidifier. Depending on the design of the humidifier the filter may be under a top cover on the top of the unit, or slide out from a side of the unit. The filter is generally located where the fan blows the moisturized air out of the unit.
Remove the water tank or remove the water fill cap and dump the existing water.
Refill the water tank or compartment with bottled water, distilled water or filtered water.
Replace any cover or panel you removed to access the filter. Plug in the humidifier and press the "On" button.
Maxwell Payne has been a freelance writer since 2007. His work has appeared in various print and online publications. He holds a Bachelor of Science in integrated science, business and technology.