Air Purifier vs Humidifier - What Is the Difference?

What is the difference between an air purifier and a humidifier? Quite a bit, actually, as we’ll discuss in this piece dedicated to examining the differences in choosing an air purifier vs. humidifier for your home. In short, the main difference is that humidifiers add moisture to the air in your home, while air purifiers do not add a warm mist or cool mist of water vapor to the air. Rather, they filter the air by trapping impurities in a filter such as dust, pollen, small particulate matter (PM2.5) and other particles that can be harmful to your health.

Studies have shown that using an air purifier in your home can help improve at least one measure or marker of improved health outcome.¹ It should be noted that an air purifier isn’t a silver bullet but can go a long way to improve your indoor air quality along a multi-pronged approach that includes both reducing the source of pollutants and improved ventilation.²

Humidifiers, on the other hand, do not work to filter impurities from the air. In fact, as you’ll see in some cases, humidifiers can be overused to the point that they create environments that are friendly to mold and other microbes, which generally should be avoided by everyone, but especially the very young, very old and other sensitive groups.

In the sections below, we’ll outline the similarities and major differences between home humidifiers and air purifiers as well as answer the question, “do air purifier work?” Read on for the facts so you can make a decision whether one is better for your family’s needs, or if you would benefit from having both in your house.

Air Purifier vs Humidifier vs Dehumidifier

Air purifier vs humidifier vs. dehumidifier: A comparison chart:

The above table will give you an idea of the utility and benefits of air purifiers and dehumidifiers as well as standard humidifiers.

When choosing an air purifier, it’s very important to choose one that uses a HEPA (High Efficiency Particulate Air) air filter and ideally also an activated carbon filter. As their name suggests, HEPA filters provide a high degree of air filtration by filtering out the tiniest airborne particles, from pet dander to pollen and dust.

A HEPA filter is generally considered the gold standard in filtration because it affords a high level of effectiveness at capturing airborne particles. Likewise, air purifiers with activated carbon filters also absorb Volatile Organic Compounds (VOCs) from the air as they pass through the filter. When combined with a HEPA filter, activated carbon filters can be an excellent choice for creating healthier, breathable air in your home. (Note: certain air purifier types, such as ozone purifiers, lack scientific basis for their claims and are ineffective in controlling indoor air pollution,, a fact that is backed up by the United States Environmental Protection Agency (EPA).⁴

A humidifier, on the other hand, is good for a single purpose: to add moisture to the air. By contrast, dehumidifiers remove moisture from the air. More on that below.

Do Humidifiers Also Purify Air?

Most humidifiers contain a filter which will only help filter large particles. Therefore, they typically aren’t effective in purifying the air of small particles and irritants. Humidifiers are used to add moisture to the air via a cool mist, which makes them a good option for those who live in dry, arid climates such as those found in large parts of the Western United States. Again, humidifiers essentially serve one purpose: to add moisture to the air.

Is an Air Purifier Better Than a Dehumidifier?

Both air purifiers and dehumidifiers are helpful tools in many households, but they serve very different purposes. Air purifiers tend to be more beneficial for people who are interested in promoting cleaner, healthier indoor air because they can help filter airborne particles like dust, pet dander, pollen and other impurities found in the air. Dehumidifiers can remove moisture from homes found in overly-humid climates, but do little to clean the air. For that purpose, you’ll want to use air purifiers, particularly ones with HEPA filters.

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Benefits of Air Purifiers, Humidifiers, and Dehumidifiers

Air Purifier Benefits

Air purifiers can deliver a host of benefits for anyone interested in cleaner, healthier indoor air. Some of them include:

Help reduce pollen, dust and tobacco smoke circulating in your indoor air
Reduce harmful fine inhalable particles (PM 2.5)
Help filter odors and VOCs (air purifiers with an activated carbon filter
Improved indoor air quality in the home

Humidifier Benefits

Humidifiers come with their own potential benefits, separate from those found in air purifiers. They include:

Help relieve the physical discomforts of dry nose, throat, lips, and skin⁵
Improved home comfort in arid climates
Reduced dry skin for those living in dry climates

Dehumidifier Benefits

By removing moisture from the air, dehumidifiers also bring potential benefits, particularly to those who live in very moist climates, such as:

Reduce environments that encourage mold growth and cozy homes for dust mites
Improved home comfort in humid climates

Air Purifier vs Humidifier for Different Situations

Air purifiers and humidifiers can be very beneficial for a variety of people, as long as they’re used properly. Sometimes they can be used together for added benefits, while other times they are best used separately. We’ll take a closer look at specific scenarios in the sections below.

Air Purifier vs Humidifier for Baby Room

When setting up your baby’s room, there’s a lot to consider, but we recommend you factor in both the quality and humidity levels of the air in baby’s living space. To solve the whole air purifier vs humidifier for baby dilemma, consider this: infants and toddlers can benefit from a combination of air purifiers and humidifiers to help keep the air at optimal humidity while filtering dust, pollen and other impurities. This advice does come with a word of caution: while it’s perfectly fine to run an air purifier 24/7, you should take care to not run a humidifier constantly. Doing so can cause moisture problems as well as the buildup of bacteria and mold spores. That’s something most adoring new parents want to avoid when it comes to their baby’s immune system!

Air Purifier vs Humidifier for Asthma

For asthma sufferers living in dry climates (or anyone in dry regions, for that matter), adding a humidifier to your home can may ease breathing for those who have asthma, especially during a respiratory infection such as a cold – just ensure you are properly maintaining the humidifier so that it doesn’t contribute to the problem.⁵ Air purifiers, on the other hand, can help reduce airborne particles such as pet dander, dust, pollen and more.

Air Purifier vs Humidifier for Allergies

High quality air purifiers as well as highly rated air filters in your HVAC system can filter many airborne allergens. Allergy sufferers living in dry climates can benefit from the use of humidifiers, as well.⁶

Air Purifier vs Humidifier for a Cold

When you’re under the weather with the common cold or flu, air purifiers and humidifiers will not cure what ails you, but they can make the experience a lot more comfortable. By soothing your nasal passages and removing impurities from the air, your time spent in bed or on the couch may be improved because colds can easily dry out your sinuses and throat.

More information:

Do I need an air purifier?

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