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The Best Air Conditioner Filters For Allergies

The Best Air Conditioner Filters For Allergies

Learn about how HVAC air filters work, some of the common types, and how their effectiveness is rated.

Are you suffering from seasonal pollen or dust allergies? You’re not alone. In fact, statistics report that 1 in 5 Americans suffer from a kind of allergy or related asthma reactions. Medication and doctor visits to treat reactions costs Americans an average $7.9 billion annually. No one enjoys constant sneezing, burning eyes, and itchy throats.

What can you do? Besides thoroughly cleaning your houses and keeping the windows closed, you should properly maintain your HVAC system. If you change the air filter at least once a month, you’ll prevent the buildup of dust and particles. If you keep the humidity below 50%, mold and other bacteria are less likely to develop.

You should also wipe the vents from time to time clear buildups of dust. If you have severe allergies, you may want to hire a professional cleaning service to clean deeper down into the vent system. You should attempt deep cleaning at least once a year anyway.

What are Allergies?

First of all, you might feel irritated from a number of triggers. Don’t jump to blame your HVAC system! It’s important to understand your exact condition. You may wish to consult a professional allergist. Knowing is half the battle!

An allergy, in a general sense, is an abnormal reaction from your immune system to an outside condition, such as food, air quality, or drugs. Normally, your body will fight off common bacteria found the environment. Some people, however, have a chemical imbalance in their system that results in relatively harmless substances (dust, latex, peanuts, etc…) being mistaken as dangerous. The body will then react by deploying antibodies to attack the targets on the body, making you feel uncomfortable. Unfortunately, there are no cures for any allergy condition.

Common Allergies and Symptoms

Most allergies have minor levels of discomfort that can be treated with medication or avoiding contact with the trigger.

In some cases, allergic reactions may be life-threatening, especially if you have existing health issues like asthma or bronchitis. Allergies to certain medications can complicate treatments and potentially be lethal. You should tell your doctor about any allergies you may have before asking for a prescription.

  • Food Allergies – The exact cause of most aggressive immune reactions to foods is unknown, but common symptoms include skin hives, digestive issues, and swollen airways (which may result in fatal choking!). Usually, a simple antihistamine injection will ease discomfort.
  • Latex Allergies – certain proteins found in latex rubber can irritate some people’s skin and cause painful rashes and may last a few hours to days after contact. Antihistamine drug can immediately treat it, but severe cases will require hospitalization.
  • Bacterial Allergies – some microscopic organisms found in dust, fungus, or mold can create an adverse reaction to in your lung system, creating nasal congestion, watery and burning eyes, and itchy skin. Specialists recommend over-the-counter antihistamines or nasal sprays to treat symptoms.
  • Pet Allergies – certain proteins created from animal fur, saliva, and urine can cause an abnormal reaction in your immune system. If you experience near immediate skin hives and sneezing after playing with your cat or dog, you probably have an allergy to them. Fur and dander in the environment can trigger a reaction even the animal itself isn’t present. While no animal will be “allergy free,” some pet breeds are more hypoallergenic than others. Always wash your hands after playing with your pets and avoid contact with stray animals. For treatment, you can use an ordinary antihistamine-based drug or consider immunization shots.

How do Air Filters Actually Work?

HVAC systems can eliminate microscopic bacteria and animal residue from circulating and polluting the indoor air quality. However, most only block the material. Other, more efficient, HEPA models will kill the substances.

Air filters are sheets with a cross fiberglass mesh designed capture dust particles. They usually vary in size by the manufacturer, but have a standard width of 1”. This mesh pattern traps large particles and contaminants and prevents them from entering the open air of your home.

Your outdoor unit will naturally bring in dust particles; most burn up by the furnace or coiling system. The remaining dust particles flow through your duct system. Filters then trap them before they reach the open air.

Eventually, though, the dust will clog the filter to the point that it doesn’t output the same level of cool or warm air, meaning you will need to replace it. You should inspect your filters about once a month and use good judgment.  

However, if you have pets or are a smoker, you might need to change it more often. You’ll find several unexpected benefits of air duct cleaning, including saving money on your electric bill by increasing efficiency. During the winter months, the indoor air quality can significantly impact someone who suffers from winter allergy symptoms; check out our helpful blog about winter allergies and HVAC maintenance tips.


The minimum efficiency reporting value (MERV) measures the effectiveness of different air filters based on the micrometer level of particles they can block. Filters can vary in price based on their MERV rating, from about $3 to $50. The standard rating scale ranges from 1-16. A higher rating equates to greater efficiency at blocking smaller particles because of their very thick microfiber messes:

MERV 1-4: These provides very minimum filtration and prevents material like dust, paint chips, and carpet fibers from escaping. They are only instrumental at block pollutants larger than 10 micrometers.

MERV 6-8: As the most common grade filters used residential and industrial buildings, these offers quality filtration of common contaminants, such as animal dander, cement dust, and mold spores. Often brands of this grade offer a cloth or paper screen cover.

MERV 9-12: Filers of this range provide high-quality air cleaning and can capture microscopic particles of 1 micrometer or larger.- MERV 13-16: High-efficiency filters in this range filter the smallest of particles, down to .3 micrometers in size, including nicotine smoke and paint and makeup pigments. Hospitals and medical labs use these kinds of filter because they require very sterile environments.

MERV 13-16: High-efficiency filters in this range filter the smallest of particles, down to .3 micrometers in size, including nicotine smoke and paint and makeup pigments. Hospitals and medical labs use these kinds of filter because they require very sterile environments.

Air Filters Ranked by MERV Rating

Compares the Effectiveness Air Filtration Devices Based on the Minimum Efficiency Reporting Value (MERV)

Other Filter Rating Systems


This system was developed by 3M. It stands for Micro-Particle Performance Rating and only takes into account a filters ability to capture small particles from 0.3 to 1 micron. It’s a scale from 300 (least effective) to 2800 (most effective).


Filter Performance Rating (FPR) was developed by Home Depot for the products they carry. It takes into account a filter’s ability to capture large and small particles. It is a scale from 4 (least effective) to 10 (most effective).

Keep in mind that the MERV rating is the only universal standard. It is regulated by the American Society of Heating, Refrigerating, and Air Conditioning Engineers. Because the organization is an independent third party (whereas Home Depot and 3M are not), it should be considered the most trustworthy rating system.

What about HEPA air filters?

Some filters go beyond the standard MERV rating and rank with a score from 16-20, meaning they can capture 99.97% of materials smaller than .03 micrometers. The government initially commissioned these high-efficiency particulate air (HEPA) filters to trap radioactive particles from the Manhattan Project during World War II. Today they have a wide variety of applications, including clearing smoke after a fire and containing material at nuclear power plants and in biomedical laboratories.

Commercial brands offer portable air purifying units marketed to allergy and asthma proof a room. Some vacuum cleaners also use a kind of HEPA technology in their filters. High-end HEPA even uses ultraviolet ray reflectors to kill bacteria, instead of just capturing it.

You may find HEPA filters expensive, loud, and bulky hunks of machinery, but also the most efficient air filters for extreme lung conditions. Beware, however, as many brands may try to use the “HEPA” term in their marketing but not actually be approved by Department of Energy, using cunning words like “HEPA-type” or “99% HEPA”.

Do some serious research, compare brands, and watch for the label “True HEPA” that indicates genuine HEPA technology.

For even more efficiency, you could invest in the ultra low penetration air (ULPA) that can capture 99.999% of material smaller than 100 nanometers.


Most HEPA devices use mechanical fans to force particles through a channel of thousands of fiberglass meshes. Regular air filters just rely on the airflow of the duct system from the outside unit. You might be annoyed at the noise level of the mechanical HEPA fans, but you can simply lower the setting. These units can also cost more in the long run since they require more electrical power to run the fan’s motor.


Other brands electrically charge the trapped air particles in an ionized field within a pre-filter. The system essentially negatively charges the dust and dander that then is attracted to the positively charged filter plates.

While highly effective, these units can create a significant level of ozone that irritates respiratory systems. Additionally, since the units negatively charge material, any escaping dust will stick to walls and other surfaces. However, the filters last longer since you can just wipe the pre-filter electronic plates to remove most particles before they reach the main filter.


Some types of HEPA units use both a mechanical and ionic technology. These purifiers can have lower fan annoyance and a combined higher efficiency of filtration.

Gas phase

Specially designed add-ons to HEPAs can capture smoke, cooking gases, and other fumes by activating carbon molecules. These thin black plates quickly become clogged with high volumes of smoke, and you should likely change it every month.

Thankfully, brands offer relatively inexpensive replacements. If you’re a heavy smoker, this type of model will be best for you.

What are the Best Filters for Allergy Relief?

To sum it all up, you want to purchase HVAC filters with a high MERV rating or equivalent. These filters will capture the most particles, even those of incredibly small size. With a high-quality HVAC filter and a commitment to keeping the windows closed and the home clean, you’ll find the most significant relief for your allergy symptoms. Of course, you should always consult with your doctor about your symptoms as well.

Finding the right air filtration system of allergies doesn’t have to be a hassle. We understand the challenge allergies cause to your livelihood and wallet. Give North Augusta Air a quick call for your needs today.


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