What Is White Dust and Should I Be Concerned About It?

HVAC Logo IconBy Tom MoorAugust 1, 2023


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Despite our best efforts to keep it at bay, dust is part our lives. Dust can come from several common sources, including our skin, fabrics, pets, allergens, and outdoor particles. But did you know dust can even come from water? It’s true.

Certain types of humidifiers which distribute mist in the air to raise indoor humidity levels during dry conditions can contain high concentrations of minerals, typically from a hard water supply. When the mist travels throughout your home and settles on tables, furniture, and other surfaces, it dries out and leaves behind mineral deposits that are referred to as white dust because of its white color.

While white dust isn’t a health concern for most people, like all dust, it can be problematic for people with allergies, asthma, or other respiratory illnesses.

What Is White Dust?

Two types of humidifiers produce white dust: ultrasonic humidifiers, which can either be portable or whole-house models, and portable impeller humidifiers. The white dust they disperse is a natural by-product of the minerals – primarily calcium and magnesium – found in the water you fill your humidifier with.

Ultrasonic and impeller humidifiers produce humidity through a steaming process, so when the water inside the humidifier is heated, it turns to vapor which is then sprayed out of the humidifier in a mist form. Within this mist are dissolved minerals from the water itself. The minerals land on furniture, tables, countertops, etc., creating the white dust you see.

The hardness of your water will decide how heavy or light this layer of white dust is (hard water is rich in minerals so the harder your water is, the more dust you can expect to find). Many homeowners who live in regions of the country with hard water install water softeners to reduce the quantity of minerals in the water.

White dust can be cleaned off just as any other household dust, so no special treatment is needed.

Is White Dust Harmful?

The white dust from humidifiers is not harmful in any way. Ingesting or inhaling small amounts of this dust is generally considered safe.

However, the presence of white dust may indicate that the air in your environment is too dry, which can have potential health effects. Dry air can cause or exacerbate respiratory issues, such as dry throat, nasal congestion, dry skin, and irritated eyes. It can also worsen symptoms for individuals with allergies, asthma, or other respiratory conditions.

How to Get Rid of White Dust in House

Fortunately, you can get rid of white dust from humidifier in a few simple ways, including:

Using Distilled Water to Fill Your Humidifier Tank

Using distilled water instead of tap water to fill your humidifier will significantly reduce white dust. Distilled water has a very low mineral count, and, therefore, will not produce the white dust that hard tap water will.

Purchase a Demineralization Cartridge

A demineralization cartridge is specifically designed to trap the minerals before they become airborne in your home. This will reduce or completely eliminate white dust in the house.

Purchase an Evaporative Humidifier

If your water is really hard and the dust is too much to handle, it may be a good idea to invest in a portable warm or cool mist evaporative humidifier. These humidifiers do not operate in the same fashion as ultrasonic humidifiers and will not disperse a layer of white dust. The only difference to watch out for is the noise level, as they are a bit noisier than ultrasonic models.

Ensure Proper Ventilation

Ensure proper ventilation in your living space to allow for the circulation of air. Good ventilation helps prevent moisture accumulation and reduces the concentration of airborne particles.

FAQs on White Dust

Is white dust harmful to health?

White dust contains the same minerals that are found in your home’s drinking water, so it does not pose any significant health risks. However, in general, a high concentration of dust can exasperate health issues for those with allergies and asthma.

What causes white dust in home?

White dust is most commonly caused by minerals found in your home’s hard water supply. When the mist from your humidifier settles on furniture and surfaces, it dries up and leaves the hard minerals behind, causing a buildup of white dust.

How do you get rid of white dust?

Two of the easiest ways to eliminate white dust in your home is installing an evaporative humidifier or using distilled water to fill the humidifier. Distilled water has a very low mineral count.



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