(Last Updated On: June 26, 2023)

Air Purifiers vs. Dehumidifiers


When it comes to combating mold spores in your home, choosing the right device can be a real game-changer. Is it better to have clean air or dry air? We will guide you through an in-depth comparison between these two popular tools. We will evaluate their effectiveness, operational mechanisms, and best-use scenarios to help you make an informed decision. 

air purifier and dehumidifier on white background

Conditions Favorable for Mold Spore Proliferation

Mold spores are the microscopic “seeds” produced by mold fungi for the purpose of reproduction. They are ubiquitous in both indoor and outdoor environments, given their ability to survive in harsh conditions. When these spores land on a suitable surface, and in the presence of moisture, they can begin to grow and multiply, forming a visible mold colony.

Mold spores thrive in conditions of warmth, darkness, and moisture. Damp environments, such as bathrooms, kitchens, basements, or any area with water damage, are prime locations for mold growth. Certain materials also promote mold growth, including wood, paper, carpet, foods, and insulation materials. Importantly, mold can start growing within 24 to 48 hours in the right conditions.

Health Implications of Exposure to Mold Spores

Exposure to mold spores can lead to a variety of health problems, especially in individuals with mold allergies or weakened immune systems. These issues range from minor irritations to more serious conditions.

Minor irritations can include allergic reactions, such as sneezing, runny or blocked nose, red eyes, and skin rashes. More severe reactions, like difficulty breathing or anaphylaxis, can occur but are less common.

Chronic exposure to mold spores can lead to more serious health issues like mold-induced asthma or hypersensitivity pneumonitis. For individuals with weakened immune systems, such as those with HIV/AIDS or those undergoing cancer treatment, exposure to certain types of mold spores can lead to serious fungal infections.

Understanding the nature of mold spores, their optimal growing conditions, and the potential health risks they pose is crucial in taking the necessary steps to control their presence and impact.

How Air Purifiers Work to Filter Mold Spores

Air purifiers work by pulling in air from your environment and passing it through a series of filters to remove contaminants. In the case of mold spores, the air is first typically passed through a pre-filter that captures larger particles. The air then moves through a more refined filter—often a High Efficiency Particulate Air (HEPA) filter—that can capture microscopic particles, including mold spores.

Most mold spores range from 1 to 30 microns in size, and true HEPA filters are capable of capturing 99.97% of particles that are 0.3 microns in diameter. As such, they are highly effective in trapping mold spores. Once captured, the mold spores remain in the filter, preventing them from being released back into the air.

Overview of the Best Air Purifiers for Mold Spores

Here are some top-rated air purifier brands and specific products known for their effectiveness against mold spores:

IQAir HealthPro Plus Air Purifier. It features a HyperHEPA filter that surpasses the standard HEPA rating, capable of filtering particles down to 0.003 microns.

Rabbit Air MinusA2. This air purifier offers a 6-stage purification and deodorization system, including a BioGS HEPA filter and optional customized filter choices that target specific concerns like germs or toxins.

Alen 75i Air Purifier. This model offers HEPA filtration and customizable panels to suit various needs and room aesthetics. The HEPA-Silver filter option is specially designed to prevent mold and bacteria growth.

Blueair Blue Pure 211+. This model combines electrostatic and mechanical filtration technologies to capture pollutants, including mold spores. Its filters also have an added antimicrobial treatment to prevent bacterial growth.

Coway Airmega 400. This purifier offers a dual filtration system (including a True HEPA filter) to capture and reduce up to 99.97% of particles in the air.

Dyson Pure Hot+Cool HP04. Dyson combines air purification with climate control features, including heating and cooling options. The HEPA filter captures 99.97% of allergens as small as 0.3 microns.

Types of Air Purifier Filters that Work To Eliminate Mold Spores

HEPA Air Purifiers: As mentioned, HEPA air purifiers are incredibly effective at trapping mold spores due to their ability to capture tiny particles. It’s crucial, however, to ensure you are purchasing a purifier with a “True HEPA” filter for optimal results.

UV Air Purifiers: These purifiers use ultraviolet light to kill or neutralize microorganisms that pass through them, including mold spores. While they don’t physically trap the spores, they can render them inactive, reducing the risk of mold-related health problems.

Activated Carbon Air Purifiers: While not as effective as the first two at dealing with mold spores, activated carbon filters can absorb moisture, helping to reduce the humidity that encourages mold growth. These are often used in conjunction with HEPA or UV purifiers for a more comprehensive solution.

Air Purifiers with Antimicrobial Treatment: Some air purifiers incorporate an antimicrobial treatment that can kill mold spores upon contact. This adds another layer of protection against mold.

Remember, the effectiveness of an air purifier in dealing with mold spores also depends on factors such as its size relative to the room, its position, and how often it is running. Regular maintenance, including replacing or cleaning filters as instructed by the manufacturer, is also crucial to ensure the purifier continues to work effectively.

What Are Dehumidifiers?

Dehumidifiers are devices designed to reduce the level of humidity in the air. High humidity levels create a favorable environment for the growth and proliferation of mold spores. By reducing the moisture in the air, dehumidifiers can help to prevent the conditions that allow molds to thrive.

Dehumidifiers operate by drawing in air from the surrounding environment, cooling it to condense the moisture out of it, and then reheating it and releasing it back into the room. The condensed water is collected in a tank that needs to be regularly emptied, or it can be directed to drain out of the unit, depending on the model.

Role of Dehumidifiers in Controlling Mold Spores

Mold spores require a certain level of moisture to germinate and grow. By reducing the humidity in a room or building, dehumidifiers make the environment less suitable for mold proliferation. Dehumidifiers do not kill mold spores or remove them from the air, but by controlling the moisture level, they can effectively help prevent new growth. It’s important to note that existing mold must be removed physically as the dehumidifier will not eliminate it.

Pros and Cons of Using Dehumidifiers


  • Prevents Mold Growth: By reducing moisture levels, dehumidifiers can help prevent the growth of mold and other moisture-loving organisms.
  • Improves Air Quality: By reducing humidity, they can also make the environment less hospitable to dust mites, another common allergen.
  • Comfort: High humidity can make environments feel stuffy or uncomfortable. Dehumidifiers can help improve the overall comfort of your home.


  • Does Not Remove Mold Spores: While dehumidifiers prevent mold growth by reducing moisture, they do not remove existing mold spores from the air.
  • Maintenance: Dehumidifiers require regular emptying of the water tank, unless a continuous drain is set up.
  • Energy Use: Dehumidifiers can use a significant amount of energy, especially if they’re running frequently.

Given their role in preventing mold growth, dehumidifiers can be a valuable tool in the fight against mold allergies. However, they should be used as part of a comprehensive approach that includes air purifiers for best results.

Air Purifiers vs. Dehumidifiers: A Comparison

Effectiveness in Dealing with Mold Spores

Air purifiers and dehumidifiers tackle the problem of mold spores differently. Air purifiers directly filter mold spores from the air, capturing them in their filters, particularly if the purifier uses a HEPA filter. Some air purifiers with UV light can also neutralize mold spores, rendering them harmless.

Dehumidifiers, on the other hand, work by reducing the humidity levels in your space, making the environment less conducive for mold growth. They don’t directly capture or kill mold spores, but they help control new mold growth by addressing one of the key conditions mold needs to thrive – moisture.

Cost Comparison

The cost of both air purifiers and dehumidifiers can vary widely depending on the model, brand, and specific features. In general, basic models of both appliances start at a similar price range, but high-end air purifiers, especially those with advanced filtering technologies, can be more expensive than high-end dehumidifiers. It’s also important to consider ongoing costs such as electricity and replacement filters for air purifiers or upkeep for dehumidifiers.

Suitability for Different Environments

Air purifiers are usually most suitable for environments where the air contains a high concentration of allergens, pollutants, or mold spores. They’re excellent for maintaining general air cleanliness in any space.

Dehumidifiers are particularly suited to environments with high humidity levels, such as basements, bathrooms, or other damp areas where mold is likely to grow. They’re also beneficial in geographical locations with a naturally high humidity level.

Maintenance Requirements

Both devices require regular maintenance, but the nature of the maintenance differs. Air purifiers require regular filter changes, with the frequency depending on the model and usage. Some may also require occasional cleaning.

Dehumidifiers generally require the water tank to be emptied regularly unless the model is set up for continuous draining. Some dehumidifiers also have reusable filters that need to be cleaned periodically. Like any appliance, both will also need occasional checks for overall performance and possible repair needs.

Overall, both air purifiers and dehumidifiers can play a significant role in controlling mold spores in your environment. The choice between the two often depends on the specific needs of your environment, your budget, and the level of maintenance you’re willing to provide.

Using Air Purifiers and Dehumidifiers Together

Using both an air purifier and a dehumidifier in tandem can provide a comprehensive approach to mold spore control. The air purifier works to remove existing mold spores and other allergens from the air, while the dehumidifier reduces moisture levels in the environment, making it less conducive for mold growth. By tackling both the cause and effect, this dual approach can be more effective than using either device alone.

Recommended Situations for Use

Using both an air purifier and a dehumidifier together is especially beneficial in environments that are both humid and have a high concentration of mold spores or other allergens. This could include damp areas of the home like basements or bathrooms, or in any living spaces of individuals who are particularly sensitive to mold and other allergens. If you live in a geographic location with high humidity, using both devices can also be beneficial.

Practical Tips for Optimal Use

Placement: Place the air purifier in a location where air can circulate freely in, out, and around the unit. The dehumidifier should be located in the area with the highest humidity, often a basement, bathroom, or kitchen.

Maintenance: Regularly maintain both devices according to the manufacturer’s instructions, including changing or cleaning filters and emptying the dehumidifier’s water tank.

Continuous Use: Mold spores can be present at any time, and humidity can fluctuate throughout the day. For the best results, consider running both your air purifier and dehumidifier continuously or as often as possible.

Size Matters: Choose the right size air purifier for your room size to ensure it can adequately filter the air. Likewise, ensure your dehumidifier is capable of reducing humidity effectively in the space where it’s placed.

Quality Counts: Not all air purifiers or dehumidifiers are created equal. Look for air purifiers with true HEPA filters and consider dehumidifiers with automatic humidity sensing and a continuous drain option.

Remember, while these devices can significantly improve the quality of your indoor environment, they are not a substitute for professional remediation if you have a serious mold problem or for medical attention if you’re experiencing health issues from mold exposure.

In Summary

The choice between an air purifier and a dehumidifier, or indeed the decision to use both, hinges on the specific needs of your environment and your personal circumstances. Factors such as the humidity level, mold spore concentration, budget, and willingness to maintain the devices all come into play. It’s also important to remember that these devices are most effective when used as part of a broader strategy to control mold, which includes proper ventilation and cleaning, and addressing any sources of dampness in your home.

Given the many variables at play, it’s crucial to do your own research and consider consulting with professionals for advice tailored to your unique situation. A professional can conduct an in-depth assessment of your indoor environment and provide specific recommendations to effectively manage mold spores. While this guide provides a comprehensive overview, it is not a substitute for professional advice or care, particularly if you’re dealing with a significant mold issue or health problems related to mold exposure. Remember, proactive steps and informed decisions can go a long way in ensuring a healthy living environment.


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