10 Tips for Humidifier Use & Maintenance

humidifier near houseplants

The Spruce / Jorge Gamboa

Humidifiers are appliances that add moisture to the air by producing and dispersing water vapor. But not all humidifiers are created equal: There are several different design types, and a surprising number of features to choose from. Use correctly, they can solve or improve several common home and personal health issues:

  • Air that is too dry can trigger or exaggerate a variety of breathing-related health issues, such as asthma, bronchitis, COPD, and emphysema. Raising air humidity levels to at least 30 percent can improve or prevent symptoms.
  • Sinus congestion caused by cold viruses or allergies can be greatly relieved by increasing air humidity. Problems with snoring are often eliminated or greatly improved by through use of a humidifier.
  • Skin irritation caused by dry air can be relieved by humidifying the air. People who are plagued by nosebleeds may find their symptoms completely eliminated when the air is moisturized.
  • Viral infections may be less likely to take hold if air humidity is kept at an optimal level.
  • Allergy symptoms can be lessened when air is kept humidified since pollen particles don't float through the air as freely as they do in dry air.
  • Wood furniture and woodwork are less likely to dry out and crack if the home's humidity levels are kept in the target 30 to 50 percent range.
  • Moist air feels warmer and conducts heat better. In the wintertime, humidified air will feel warmer than bone-dry air.
  • Humidified air is great for indoor plants. Tropical houseplants, especially, will greatly appreciate air that is kept humidified.

But for a humidifier to perform these benefits, you must choose the right model, use it correctly, and keep it properly maintained. Here are 10 tips for getting the most out of your humidifier.

  • 01 of 10

    Use a Humidifier to Target Health Issues

    A very common reason to use a humidifier is to prevent or alleviate problems often associated with very dry air, ranging from dry skin to serious COPD breathing problems.

    While all of these issues can be alleviated through the use of a humidifier, it's important to note that too much humidity can also be an issue. Not only can over-humid air create its own health problems, but it can also cause damage to paint, plaster, and wallpaper. In addition, it's important to carefully monitor the condition of the humidifier to avoid mold or other potential allergens.

    If your goal is to address health issues, pay very close attention to the effect that results from the use of your humidifier. You may need to adjust the way you use the appliance—or even change to a different design—to get the best possible results.

  • 02 of 10

    Choose the Right Humidifier Design

    Home humidifiers come in several designs that are best suited for different purposes. In general, the various types are divided into cool mist and warm mist designs. Warm mist humidifiers generally produce a visible water vapor, while many cool-mist units produce an invisible mist.

    • Evaporative humidifiers, also known as cool moisture humidifiers, have three parts: a reservoir for cool water, a wick that absorbs water, and a fan to distribute the humidified air. As the water from the reservoir is pulled into the wick, it evaporates into the air as vapor. The fan distributes the cool humidity so it can fill the room. These are very affordable units, but they can exaggerate asthma problems unless cleaned often since they can be prone to mold growth in the reservoir and on the wick pad. These units generally do not produce a mist that is visible to the eye.
    • Impeller humidifiers: This is another type of cool moisture appliance. They work by means of a rotating disc that spins at high speed to fling microscopic water droplets into the air. If overused, they can potentially exaggerate breathing problems for people with asthma, since they may put too much moisture into the air. With this style, the water mist is often visible as it emerges from the appliance.
    • Vapor or warm mist humidifiers: This type boils water to create steam, which immediately turns to a visible water vapor that is distributed by a fan. The advantage of a vapor humidifier is that the boiling kills mold and pathogens. These are good units for people with asthma and allergies. The downside, of course, is that boiling water consumes energy and these units can cause burns if they are knocked over. Use them very cautiously where children or active pets are around.
    • Ultrasonic humidifiers: This design puts moisture in the air by means of rapidly vibrating ceramic discs that essentially pulverize liquid water into tiny droplets that are gently blown into the air. These are usually cool-air units, though there are also elaborate models equipped that boil water or use UV light to sterilize it before it is turned into water vapor. These types generally produce a mist that you can see. These are very safe units, but they may put fine particles of minerals from the water into the air. This can create a fine dust that sometimes exaggerated asthma symptoms. This fine dust may also settle on furniture and surfaces.
    • Central humidifiers: Unlike the first four types, which are usually single-room humidifiers, central humidifiers are permanent features that are installed directly on your forced-air HVAC system to serve the entire house. They come in two basic operating designs: evaporative, in which water is evaporated off a rotating drum or panel wick; and steam designs, which vaporize water by boiling it, a feature that helps sterilize the vapor and kills mold and pathogens. Central whole-house humidifiers can be quite expensive to install, but they are very effective at controlling the humidity levels throughout the house.
  • 03 of 10

    Choose the Right Size of Humidifier

    Room humidifiers come in various sizes, allowing you to match different rooms. Labeling usually identifies the unit as being appropriate to a certain square footage for the room. In addition, humidifiers can be categorized by the size of the water reservoir, or by the time they will operate between fillings. Large tanks have the obvious advantage of not needing to be refilled as often—you will never need get up in the night to refill the tank.

    In general, an average bedroom is well served by a 700–900 square foot unit. A 2- or 3-gallon humidifier will usually run from 11 to 16 hours between fillings, depending on the setting.

  • 04 of 10

    Never Add Salt to a Humidifier

    Some people imagine that you can add salt to the water in a humidifier's reservoir to create the smell and feel of salty fresh sea air. This is a very bad idea. Salt dissolved in the water can destroy any metal components, reducing your humidifier's lifespan, clogging your filter, and hindering proper operation.

    Some units are designed to allow aromatherapy oils to be added, usually in some kind of secondary reservoir or tray. That's fine, but never try to dissolve essential oils in the water that is being vaporized. As air quality experts sometimes say, "if you can smell it, it's air pollution."

    Continue to 5 of 10 below.
  • 05 of 10

    Cool Mist and Warm Mist Humidifiers Have Different Advantages

    Cool mist and warm mist designs have different advantages and different health and safety profiles. It's even possible you will want to own both designs to use as appropriate.

    Cool mist is safer if you have safey concerns about boiling water. In bedrooms with active toddlers or rambunctious pets, the dangers of having an appliance that boils water is self-evident. Within the cool mist category, simple evaporative humidifiers are less likely to put water mineral particles in the air—a possible drawback with the ultrasonic design.

    However, a warm mist humidifier can be considered a better health choice if you are concerned about possible mold or mildew in your humidifier. This can be extremely important for users with allergies, or for whom mold serves as an asthma trigger. All things considered, warm mist is often the better choice for people with asthma.

  • 06 of 10

    Humidifiers Sometimes Makes Asthma Worse

    It's often assumed that a humidifier is an excellent way to minimize symptoms of asthma, COPD, or other bronchial problems. Yet unless it is used exactly correctly, a humidifier can make these conditions worse. Ideally, room humidity should be between 30 and 50 percent, and if the humidifier is overused, it can exaggerate breathing problems. Further, humidifiers that become laden with mold can cause severe allergic reactions, which is often the trigger for an asthma attack. Finally, ultrasonic-type humidifiers also put tiny particles of water minerals into the air, which can trigger asthma attacks.

    For asthma sufferers, a warm-mist humidifier, or evaporative humidifier with a UV feature to kill pathogens is often the best choice. And it must be used carefully to keep the air humidity at the optimal level.

  • 07 of 10

    Humidifiers Must Be Regularly Cleaned

    To be safe and healthful, all humidifiers should be cleaned and sterilized regularly. Even steam humidifiers or those with UV disinfectant features will gradually build up mineral deposits that affect their operation.

    Carefully follow the manufacturer's recommendations for cleaning the unit, and if your model has a wick or pad, make sure to replace it at the intervals suggested.

  • 08 of 10

    Choose the Features You Need

    Room humidifiers come in a wide range of features, from very simple desktop humidifiers that add a bit of moisture without any kind of timer or humidistat controls, to elaborate console models equipped with filters, UV lights to sterilize water, colorful glowing night lights, essential oil diffusers, humidistat controls, automatic timer shut- off, LED displays, and quiet-operation modes for nighttime use.

    Think carefully about the features you will really use. These are not expensive appliances, but it doesn't make sense to pay for features you don't need. At the very least, though, it makes sense to have a unit with a humidistat feature that senses the air moisture level and adjusts its output to maintain an optimal level.

    Continue to 9 of 10 below.
  • 09 of 10

    Run the Humidifier Day and Night

    During the season when air humidity levels are low, it's usually best to run the humidifier constantly, provided it has a built-in humidistat that senses air humidity levels and controls the output of the appliance.

    The rules are a little different if you are using a humidifier simply to control the air quality during the night. For example, some people like to humidifier air in the bedroom at night to reduce snoring. Or, you may want to give tropical plants a periodic blast of super-humid air. Here, using the appliance for "spot use" is fine.

  • 10 of 10

    Use the Appliance Correctly

    In climates where the air is very dry—if you live in the desert, for example, or in a cold climate that has very dry winter months—there is little chance that you will over-humidify your home. But with a large, robust humidifier, it is possible to put so much water moisture into the air that you cause wallpaper to peel or foster the growth of mold on walls, furniture, or carpeting.

    To avoid these problems, keep the air moisture levels at 30 to 50 percent, and never over 60 percent— this range is comfortable to most people and prevents most of the problems caused by too little or too much moisture in the air. Your humidifier should have a humidistat that allows you to keep the air moisture within that range.