Air Purifier  vs. Humidifier: Which One  Do You Need?

Air purifiers and humidifiers can both impact the air you breathe in your home, but they each serve a different purpose with unique benefits. If you are looking for ways to help allergies, issues with your respiratory system, or dry air conditions, you should understand the differences between an air purifier and a humidifier, and how to use each one most effectively.

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What is the difference between an air purifier and a humidifier?

An air purifier is used to clean the air by removing or otherwise “inactivating” pollutants from the air. The two basic components of an air purifier are a fan and a filter surface, though the specific filtration technology can vary. In most purifiers, air is passed through the unit, pollutants are trapped or removed on an air filter and clean air is emitted back into the room. Air purifiers do not add any moisture to the air.

A humidifier, on the other hand, does not clean the air. It simply adds water to the air by boiling water into steam, vibrating water droplets into the air with ultrasonic technology, or by evaporating the water using a fan and a wick.

Because ultrasonic humidifiers might introduce tiny mineral particles into the air if tap water is used, the EPA recommends using distilled water and regularly cleaning and disinfecting your humidifier.

How do air purifiers and humidifiers impact your health?

For babies

The FDA states that using a cool mist humidifier may help infants who have cough and cold symptoms, by shrinking nasal passages and helping them breathe easier. However, a warm mist humidifier should not be used, as it can have the opposite effect by causing nasal passages to swell, making breathing more difficult. When humidifiers are used to maintain an ideal relative humidity of 40 to 60 percent, they can also reduce the infectiousness of bacteria and viruses.

For babies

For long term air quality, an air purifier can reduce pollutants in the air, including potential toxins from tobacco smoke, “out-gassing” plastics, allergens and asthma triggers like mold spores or pet dander and pollen, and other possible respiratory irritants.

Tobacco smoke

Pet dander

Black mold


For allergens

An air purifier can help reduce allergen levels in the air. Though humidifiers may help soothe a stuffy nose or other irritation, they can actually make allergies worse because higher humidity improves the survival rates of dust mites.


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A humidifier can ease asthma symptoms if dry air is also a problem, but it does not affect asthma itself, and higher humidity levels are actually associated with asthma attacks because they can trigger the growth of harmful bacteria, dust mites and mold 

Since asthma attacks are often triggered by airborne pollutants  in the air, an  air purifier  that can  remove those  pollutants is better for asthma.

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Can I use both an air purifier and humidifier together?

Because both an air purifier and a humidifier perform completely different functions (removing pollutants from the air as opposed to adding moisture to the air), they can be used together, even in the same room. However, you should avoid placing them too close together because the moisture from the humidifier could clog filters or otherwise limit the effectiveness of the air purifier, and even promote growth of mold or bacteria on the filter. This can be avoided by placing them at opposite ends of the room.

Remember that a humidifier must be kept clean, ideally allowed to dry and be wiped down every few days after use. Otherwise, mold can form inside or on the humidifier, and it will then emit mold spores into the air, triggering the kinds of allergy or asthma attacks you want to avoid. For an air purifier, maintenance primarily means replacing filters regularly.