A humidifier adds moisture to the air by releasing a fine mist or water vapor.
How it works
A humidifier adds moisture to the air.
- Cool mist (ultrasonic): a vibrating plate breaks water into a fine mist.
- Evaporative: a fan blows air over a wet wick.
- Warm mist (steam vaporizer): heats water to produce steam.
Ideal humidity
The EPA recommends 30 to 50 percent indoors. Above 60 percent encourages mold and dust mites.
Benefits
Eases dry skin, dry throat and nasal irritation.
Care
Clean every 1 to 3 days. Use distilled water to avoid mineral dust. Change filters.
Safety
Warm mist can cause burns.
Measure
Use a hygrometer.
Not for
Pets or asthma if overused.
Types
- Evaporative (cool mist with a wick and fan): the fan blows air through a wet wick, which evaporates water. It self regulates because evaporation drops as humidity rises.
- Ultrasonic: a vibrating plate breaks water into a fine mist.
- Steam vaporizer: heats water to make steam, and so produces no minerals but poses a burn risk.
- Impeller: a rotating disc flings water at a diffuser, producing a cool mist.
Why humidity matters
Indoor air in winter can fall below 20% relative humidity because cold outside air holds little moisture. Dry air can irritate skin, eyes, nasal passages and throat.
Recommended range
The EPA recommends keeping indoor relative humidity between 30% and 50%. Above 60% promotes mold and dust mites.
Water choice
Ultrasonic humidifiers can release white dust from minerals in tap water. Distilled or demineralized water reduces the dust, though some brands use filters or cartridges.
Cleaning
- Empty and refill the tank daily.
- Clean with white vinegar or 3% hydrogen peroxide every 3 days or per the manual.
- Rinse well and dry before storing.
- Replace wicks and filters as the maker advises.
Bacteria and mold
Dirty tanks may release bacteria and mold spores, causing breathing problems. Humidifier fever is a flu like illness that has been linked to contaminated units.
Placement
Put on a flat surface at least 2 to 3 feet away from beds, 12 inches from walls and away from electronics and wood furniture.
Safety with children
Hot steam vaporizers can cause burns. Cool mist units are generally recommended for children’s rooms.
Mechanisms and types
Evaporative humidifiers draw water through a wick with a fan, ultrasonic ones use a vibrating plate to create a cool mist, and steam vaporizers boil water. Warm mist units produce steam that can burn, so they are not advised near young children. Humidifiers can ease dry skin, nosebleeds and dry throat in winter, when indoor humidity can drop below 20 percent. The EPA recommends keeping indoor relative humidity between 30 and 50 percent, since levels above 60 percent promote dust mites and mold. Use a hygrometer, which costs about 10 to 20 USD, to measure it.
Maintenance and water quality
The tank should be emptied, rinsed and refilled daily, and cleaned with a vinegar solution or manufacturer approved cleaner every 3 days. Standing water can grow bacteria and mold, and mist can spread them, leading to “humidifier fever,” a flu like illness. Using distilled or demineralized water reduces the white dust that ultrasonic models spread, which is mineral residue that can irritate the lungs. Place the unit on a flat surface at least 2 feet from walls, and do not let surfaces feel damp. The Consumer Product Safety Commission has reported burn injuries from hot water vaporizers in children, so use cool mist models in children’s rooms.
Based on data from the EPA and the Consumer Product Safety Commission
