The Humidifier Experiment That Changed How I Breathe at Home
When monitoring our home environment, I discovered something concerning about humidifiers that I felt compelled to share—especially for those trying to conceive, pregnant, or with young children.
My Surprising Air Quality Experiment
I typically only use our humidifier during illness. During testing:
Our whole-house activated carbon filtered water caused air quality monitors to spike to dangerous RED levels (230+)
Reverse osmosis water with remineralization stayed in the green zone initially but gradually rose to 75 (red zone) by morning
Next, I'll test distilled water to determine if minerals are the culprit
Why This Matters for Your Health
Humidifiers can inadvertently pollute your indoor air if you're not using the right water
Minerals from filtered water become airborne and may affect lung health over time
Mold and bacteria thrive in humidifiers if they're not cleaned properly every 1-2 days. The EPA recommends disinfecting portable humidifiers every third day to reduce the buildup of scale and microorganisms.
Sustainability Tip
While distilled water is the gold standard for humidifiers, it's typically sold in single-use plastic bottles. For a more eco-friendly approach and to avoid harmful hormone disrupting chemicals from plastics, consider investing in a stainless steel or glass home water distiller. This reduces plastic waste and protects your hormones while ensuring you always have the optimal water for your humidifier.
Who Really Needs Humidifiers?
They're most beneficial:
In very dry climates
When you're congested or sick
For nasal/breathing issues
During winter when heating dries out indoor air
But used improperly, they can do more harm than good. Research from Virginia Tech has shown that running humidifiers with tap water may be risky, with conditions consistently exceeding ambient air standards set by the EPA.
The bottom line: What you put in your humidifier directly impacts what you breathe. Experts recommend using distilled water to minimize the risk of increased PM2.5 levels while using an ultrasonic humidifier, and the EPA suggests "evaporative" or "steam vaporizer" humidifiers may release fewer microorganisms than "ultrasonic" or "cool-mist" machines. For those on fertility journeys, during pregnancy, or with young children, these seemingly small choices can have outsized effects on your home's air quality and your family's respiratory health.
A comparison table outlining the best water types for use in humidifiers. The table ranks five types of water—distilled, deionized, reverse osmosis (RO), carbon-filtered tap, and straight tap water—based on how humidifier-friendly they are. Distilled and deionized water are marked in green as the best options, RO water is marked in yellow with a caution note, and both carbon-filtered and tap water are marked in red as not recommended. Each row includes a brief explanation of why that water type is or isn't suitable, with emphasis on mineral content, potential for mold or white dust, and impact on air quality.
References:
Environmental Protection Agency. Use and Care of Home Humidifiers. EPA.gov. https://www.epa.gov/indoor-air-quality-iaq/use-and-care-home-humidifiers. Published June 16, 2024. Accessed April 23, 2025.
Yao W, Virginia Tech Water INTERface IGEP. The Close to Home Issue of Humidifiers and Indoor Air Quality. Virginia Tech Civil & Environmental Engineering. https://cee.vt.edu/News-Menu/CEE_Article_Cache/IndoorAir.html. Published January 6, 2021. Accessed April 23, 2025.
PurpleAir. Ultrasonic Humidifiers: A Source of PM2.5. PurpleAir.com. https://www2.purpleair.com/blogs/blog-home/ultrasonic-humidifiers-a-source-of-pm2-5. Accessed April 23, 2025.
