Air Humidifier vs. Dehumidifier for Allergies

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Written By Jamila W.
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Air purifiers and dehumidifiers are appliances that can help improve your allergy symptoms. Indoor air quality has a big impact on the levels of common airborne particles and allergens like pet dander, pollen, and dust mites in your home’s air. Both types of air conditioning appliances can help allergy sufferers, but only one device removes them from the air. In this article, we’ll compare air purifiers and dehumidifiers to see which one is the better investment for allergy relief.

Air Purifier vs Dehumidifier for Allergies: Side-by-Side Comparison

Air PurifierDehumidifier
What is it:A device that removes airborne pollutants from indoor airAn air conditioning device that removes moisture from indoor air
Purpose of appliance:Cleansing indoor air from pollutantsReducing humidity levels in indoor spaces
Initial release:1860s1902
Developers:Charles Anthony DeaneJohn Stenhouse The Manhattan ProjectWillis Carrier (US engineer and inventor of air conditioning)
Technologies used:Mechanical filter,Ionization,Catalytic oxidation,Chemisorption,Ultraviolet germicidal irradiation Thermal condensation,Absorption/desiccant,Membrane, Ionic membrane
Types of particles removed:DustPet danderPollenFine particulatesVolatile Organic Compounds (VOCs)Inorganic gassesWater vapor
Applications: Domestic and commercial air cleaningAir purification in sensitive environmentsRemoval of airborne pollutants in electronics manufacturing environmentsRegulation of humidity in residential and commercial environmentsRegulating humidity at iceReduction of humidity and prevention of mildew in construction sitesFlood restoration Industrial processes and manufacturing

Air Purifier vs Dehumidifier for Allergies: What’s the Difference?

Air humidifiers and dehumidifiers are both used for their beneficial effects on air quality. Both types of appliances can help allergy sufferers and look extremely similar, but they have important differences that make one of them the more appropriate choice for symptomatic relief. Here are the key differences between an air purifier or dehumidifier for allergies:

What Is an Air Purifier?

An air purifier is a device that removes particulate and gaseous contaminants, including airborne allergens like pollen, tobacco smoke, and dust mite eggs, from indoor air. The air cleaning action of these appliances improves indoor air quality. Consumer air purifiers are often purchased because their reduction of indoor air pollution benefits allergy sufferers. 

The first air purifier was invented in the mid-19th century by John Stenhouse using wood charcoal to air purification purify air. Interestingly, activated charcoal continued to be one of the most effective types of air purification to the present day. 

How Does an Air Purifier Work?

Consumer portable air purifiers are usually fan-assisted devices that have an indoor air intake that is filtered and exposed to a variety of air purification technologies that trap, retain, or destroy pollutants. The exhaust air of the air purifier is clean, improving your home’s air quality. The technologies used to cleanse room air of pollutants include mechanical filtration with a HEPA filter, UV light-mediated catalytic oxidation, chemisorption, and ultraviolet germicidal irradiation (UVGI). Air purifiers differ in the technologies they use and their level of efficiency, but most devices will filter common airborne allergens.

What Is a Dehumidifier?

Photo by Yehor Andrukhovych:

A humidifier is an electrical appliance that actively removes moisture from the air using a range of air conditioning technologies. Dehumidifiers were invented over a century ago by Willis Carrier, the father of air conditioning, and continue to use refrigeration to extract water from moist air, preventing mold and mildew growth. 

How Do Dehumidifiers Work?

Most conventional dehumidifiers pass indoor air over the evaporator coils that cool and condense the moisture from the air. The action is very similar to an air conditioning unit, but as the water vapor cools beneath the dew point, the water droplets are collected, rather than being allowed to evaporate or drip outside. The collected water has to be emptied at regular intervals to ensure optimal performance of the machine. 

Other dehumidifying technologies may be used including absorption or desiccant dehumidification using hygroscopic substances to absorb water vapor from indoor air. A consumer-grade portable dehumidifier can remove between 30 and 50 liters of water from room air in 24 hours, depending on its size and specifications. 

Air Purifier vs Dehumidifier for Allergies: Effects on Allergies

Air humidifiers and dehumidifiers can both enhance indoor air quality and bring relief to allergy sufferers. But these two different types of appliances vary significantly in the impact they can have on your allergies. Let’s take a closer look at how an air purifier and a dehumidifier help allergy sufferers including the pros and cons of using each one. 

How an Air Purifier Tackles Allergies

Air purifiers are specifically designed to remove contaminants present in indoor air, including the common airborne allergens that cause conditions like:

  • Rhinitis
  • Sinusitis
  • Asthma
  • Eczema
  • Eye irritation 

By trapping or destroying common allergens like pet dander, mold spores, pollen and cockroach debris and detritus, an air purifier reduces your exposure to these allergens so that your symptoms are improved with less congested breathing and great comfort in your home. 

Most air purifiers target particulates that are known to cause the inflammatory reactions that drive allergies. High-efficiency particulate air filtration, an industry-standard targets fine particulates that research has shown to be the most damaging. 

In addition, air cleaners like ionic air purifiers will remove irritant chemicals like nitrogen dioxide, Volatile Organic Chemicals (VOCs), and ozone, which are associated with long-term health conditions like heart disease and even lung cancer. 

Pros and Cons of an Air Purifier for Allergies

Specifically designed to improve indoor air quality by removing airborne pollutantsCan remove common allergens like pollen, pet dander, and mite eggs from indoor airAble to remove microorganisms like bacteria, viruses, and mold that aggravate allergies or cause secondary infectionsCapable of removing gaseous irritants like VOCs and nitrogen dioxideAir purifiers can be run at night to improve nighttime air quality and improve sleepAir purifier activity does not impact the temperature of an indoor environmentAn air purifier cannot reduce humidity in an indoor environmentAir purifiers do not increase room ventilation.

How a Dehumidifier Tackles Allergies

Dehumidifiers do not directly remove allergens in an indoor environment. They are effective at removing excess moisture only and cannot affect the levels of common allergens. However, their effect on relative humidity is often beneficial to allergy sufferers because a reduction in water vapor can control humidity levels and reduce mold growth. 

Photo by CDC:

High humidity reduces air circulation, causing airborne allergens to persist in indoor air which can induce symptoms in room occupants. Bacteria, mold, and viruses can also thrive in a humid environment, so by tackling a room’s humidity, a dehumidifier reduces the persistence of these pollutants and the allergies caused. 

Pros and cons of a dehumidifier for allergies

Able to actively remove water vapor from indoor air and reduce the level of humidity in a roomA reduction in humidity reduces the persistence of pollutants and allergens leading to the relief of allergy symptomsLess humid air is more comfortable to breatheDehumifidiers only remove water vaporDehumidifiers cannot reduce the levels of indoor air pollutants and allergensA dehumidifier can not trap particles or remove gaseous air pollutants from room airDehumidifiers can dry air excessively which can provoke respiratory conditions like asthmaDehumidifiers cannot affect temperature or ventilation in a room

If You Have Allergies, an Air Purifier Should Be the Priority for Your Property

As you can see, an air purifier is specifically designed for the removal of airborne allergens. Air purifiers with a HEPA filter, catalytic oxidation air filters, or activated carbon filters can tackle the most common biological, organic, and inorganic allergens from the surrounding environment. This helps with asthma symptoms and other allergies.

Unlike a dehumidifier which only changes the humidity level, an air purifier will trap, retain, or destroy allergens that a present in indoor air, releasing clean air into the room. The action of an air purifier is continuous meaning that elegy suffers can benefit from sustained relief from exposure to the substances that are irritating their skin, eyes, throat, and airways.

In Conclusion

Air purifiers are the best appliance for allergies as they are the only device that will remove allergens from the air. They are unobtrusive, low-maintenance devices that are effective at reducing allergens that cause allergic reactions. Their low noise level means that they can be run 24 hours per day for a significant difference in respiratory problems. Though a dehumidifier can remove excess humidity, mildew, and mold, an air purifier is the better device to alleviate allergy symptoms and improve air quality.