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If you or your child has been diagnosed with allergies or asthma, your allergist has likely mentioned air filtration as part of your environmental control plan alongside allergen-proof bedding.
Portable air cleaners with true HEPA filtration can help reduce indoor concentrations of the particles that trigger allergy and asthma symptoms, when sized correctly for the room and run continuously. Source: U.S. EPA, Guide to Air Cleaners in the Home
But the air purifier market is crowded with vague marketing claims. "HEPA-type," "99% efficient," and "medical grade" appear on products that would not pass the actual HEPA test. This guide explains what to actually look for, walks through the real differences between true HEPA and filterless technology, and compares AllergyStore's own Austin Air, Airpura, and Airfree lines so you can match a purifier to your room and your symptoms.
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Guide Contents
What Actually Makes an Air Purifier Effective for Allergies and Asthma
Three things determine whether an air purifier will meaningfully reduce your allergen exposure: the filter technology, the airflow relative to your room size, and whether it addresses gases and odors as well as particles.
True HEPA vs. "HEPA-type"
A true HEPA filter meets a specific, testable standard: it must remove at least 99.97% of airborne particles 0.3 microns in size, the hardest particle size to capture, sometimes called the "most penetrating particle size." This is a defined engineering standard, not a marketing term. "HEPA-type," "HEPA-like," and "99% HEPA" are not the same thing and are typically well short of true HEPA performance. If a product listing doesn't state the 99.97% at 0.3 micron figure explicitly, treat it as not true HEPA.
CADR and room size
Clean Air Delivery Rate (CADR) measures how much filtered air a purifier actually delivers, in cubic feet per minute, for smoke, dust, and pollen specifically. A high-CADR unit rated for a much larger room than yours will clean your actual room faster and can run on a lower, quieter fan speed. Manufacturers list a maximum coverage area; treat that number as the ceiling for a large open room, not the size to aim for in a bedroom where you want continuous, quiet overnight operation.
Particles are not the whole story
HEPA filters capture particles: dust, pollen, pet dander, mold spores, and dust mite allergen. They do not remove gases, odors, or volatile organic compounds (VOCs). If wildfire smoke, chemical sensitivities, new-furniture or new-flooring off-gassing, or general household odors are part of your symptom picture, you need meaningful activated carbon, measured in pounds, not a thin carbon-infused pre-filter that gets saturated in weeks.
A word on certification
Some air purifier brands now carry the Asthma and Allergy Friendly® certification from the Allergy & Asthma Foundation of America (AAFA), an independent, lab-tested certification rather than a self-declared marketing claim. It's a genuinely useful shortcut when comparing unfamiliar brands, and it's a meaningful trust signal worth asking about with any manufacturer, including the brands below.
True HEPA vs. Filterless: Two Different Technologies AllergyStore Carries
AllergyStore's catalog spans two fundamentally different approaches to air purification, and understanding the difference matters more than comparing spec sheets line by line.
True HEPA + activated carbon (Austin Air and Airpura) physically traps particles in a dense filter media while a separate bed of activated carbon adsorbs gases and odors. This is the technology behind essentially every air purifier recommended by allergists and behind the EPA's guidance. It requires periodic filter replacement, typically every five years for the HEPA media on these units, but it is the most complete solution across particles, gases, and odors together.
Filterless thermodynamic purification (Airfree) uses a completely different mechanism: it draws air through a ceramic core heated to roughly 400°F using passive convection, no fan, and destroys mold spores, dust mite allergen, bacteria, and viruses with heat rather than trapping them. There are no filters to replace and no moving parts to maintain, and the units are silent. The tradeoff is that this process does not physically remove dust, pollen, or pet dander from the air, and it includes no activated carbon for gases or odors. It is a strong fit for mold- or dust-mite-driven allergy symptoms in a small room, a nursery, or anywhere silent, zero-maintenance operation matters most.
Neither approach is universally "better." The right choice depends on what's actually triggering your symptoms.
Comparing AllergyStore's Air Purifiers
| Model | Technology | Coverage | Carbon | Best for |
|---|---|---|---|---|
| Austin Air HealthMate Junior HM200 | True HEPA (99.97% @ 0.3 micron) | Up to 700 sq ft | 15 lbs activated carbon + zeolite | A child's bedroom, home office, or dorm room |
| Austin Air HealthMate HM400 | True HEPA (99.97% @ 0.3 micron) | Up to 1,500 sq ft | 15 lbs activated carbon + zeolite | General allergy and asthma control in a bedroom or open living space |
| Austin Air HealthMate Plus | True HEPA (99.97% @ 0.3 micron) | Up to 1,500 sq ft | 15 lbs potassium-iodide-impregnated carbon | Chemical sensitivities, wildfire smoke, formaldehyde off-gassing |
| Austin Air Bedroom Machine | True HEPA + HEGA gas-arrestance cloth, 5-stage | Up to 1,500 sq ft | 15 lbs proprietary carbon blend | Overnight bedroom use where sleep quality is the priority |
| Austin Air Immunity Machine | True HEPA, 8-phase filtration | Not specified for open-room coverage | Carbon + zeolite, standard and impregnated forms | Immunocompromised individuals or anyone wanting the most comprehensive filtration Austin Air offers |
| Airpura UV600 | True HEPA + in-chamber UV-C | Up to 2,000 sq ft | 18 lbs activated carbon | Mold spore and pathogen concerns alongside general allergens |
| Airpura P600 | True HEPA + UV-C + titanium dioxide photocatalytic oxidizer | Up to 2,000 sq ft | 18 lbs activated carbon | Heavy chemical, VOC, and odor abatement alongside allergens |
| Airfree P1000 | Filterless thermodynamic (heat, no filter) | Up to 450 sq ft | None | A small room, nursery, or dorm where silent, maintenance-free operation matters most |
Specifications above are drawn from each product's current AllergyStore listing.
How to Choose
Start with your room size, then size up
Measure the room, then look for a coverage rating meaningfully above that number if you want quiet, continuous overnight operation. A HealthMate Junior in a large living room will be underpowered; a HealthMate HM400 in a small bedroom can run on its lowest, quietest setting and still turn over the room's air quickly.
Match the technology to your trigger
If your main triggers are dust, pollen, and pet dander across a range of particle sizes, a true HEPA unit is the right foundation. If chemical sensitivity, wildfire smoke, or off-gassing from new furniture or renovation materials is part of the picture, prioritize a unit with a large, dedicated activated carbon bed, such as the HealthMate Plus or Airpura P600. If mold or dust mite allergen in a small, contained space is the primary concern and you want zero filter maintenance, the Airfree P1000 is a legitimate, different kind of solution.
Consider where it's going
A bedroom unit benefits from quiet low-speed operation and, ideally, features aimed at sleep, which is the specific case the Austin Air Bedroom Machine is built around. A shared living space benefits more from raw coverage area and CADR. A nursery or child's room benefits from a compact footprint and low noise floor.
Air Purifiers Are Part of a Layered Approach
An air purifier addresses airborne allergens, but dust mite allergen concentrates in mattresses, pillows, and bedding, not just in the air. A true HEPA air purifier running continuously in the bedroom works best alongside allergen-proof mattress and pillow covers, weekly hot-water washing of sheets, and keeping indoor humidity between 30 and 50%.
👉 Read: Best Mattress Protector for Dust Mites: The Complete Buying Guide
Frequently Asked Questions
What does "true HEPA" mean, and how is it different from "HEPA-type"?
A true HEPA filter meets a specific, testable standard: it must remove at least 99.97% of airborne particles 0.3 microns in size, the hardest particle size to capture. Terms like "HEPA-type," "HEPA-like," or "99% HEPA" are marketing language, not the certified standard, and are typically far less effective. If a listing doesn't state the 99.97% at 0.3 micron figure explicitly, assume it is not true HEPA.
What size air purifier do I need for my room?
Match the purifier's rated coverage area to your room, and size up rather than down. A unit rated for 1,500 square feet run in a 300 square foot bedroom will clean that air far faster and more thoroughly than a unit rated exactly for that room size run at full speed. If you sleep with the door closed and want quiet overnight operation, choosing a purifier rated for two to three times your room's actual square footage lets you run it on a lower, quieter fan speed while still getting full coverage.
Do I need activated carbon in addition to HEPA?
HEPA filters capture particles: dust, pollen, pet dander, mold spores, dust mite allergen. They do not capture gases, odors, or volatile organic compounds (VOCs). If your concerns include smoke, chemical sensitivities, formaldehyde off-gassing from new furniture or flooring, or general household odors, you need a unit with a substantial activated carbon bed in addition to true HEPA. A thin carbon-infused pre-filter is not the same thing as several pounds of dedicated activated carbon.
Is a filterless air purifier as effective as a HEPA air purifier for asthma?
Filterless thermodynamic purifiers work on a different principle than HEPA: they draw air through a heated ceramic core that destroys mold spores, dust mite allergen, bacteria, and viruses through heat rather than trapping them in a filter. They are effective against biological allergens and require no filter changes, but they do not remove dust, pollen, or pet dander the way a HEPA filter physically does, and they do not include activated carbon for chemical or odor removal. For asthma triggered primarily by mold or dust mite allergen in a small space, a filterless unit can be a genuine, low-maintenance option. For general allergy and asthma control across a full range of particles, gases, and odors, a true HEPA unit with activated carbon is the more complete solution.
Where should I place an air purifier for the best allergy relief?
Place it in the room where you spend the most consecutive hours, which for most allergy and asthma sufferers is the bedroom, and run it continuously rather than turning it on and off. Position it a few feet out from the wall with the intake unobstructed, not tucked into a corner or behind furniture. An air purifier only cleans the air that reaches it, so continuous operation in your main room matters more than moving a single unit from room to room.
The Bottom Line
Look past "HEPA-type" marketing language and confirm true HEPA performance (99.97% at 0.3 microns), size the unit to your room rather than matching it exactly, and match the technology, HEPA plus carbon versus filterless thermodynamic, to what's actually triggering your symptoms. Not sure which AllergyStore air purifier fits your space? Call us at (800) 771-2246 and we can help you match a unit to your room size and symptoms.
Shop all AllergyStore air purifiers
Sources
U.S. EPA, Guide to Air Cleaners in the Home: https://www.epa.gov/indoor-air-quality-iaq/guide-air-cleaners-home
AAFA, asthma and allergy friendly® Certification Program: https://www.aafa.org/asthma-allergy-friendly-certification-program/
Want the complete picture? Everything on this page is part of our free Practical Guide to Allergy-Free Living, 35 years of allergy expertise covering dust mites, pet dander, air quality, laundry, and more. Start at the beginning or jump to the section that matters most to you.
Medical Disclaimer: This content is for educational and informational purposes only and is not intended as medical advice. Always consult a qualified healthcare provider regarding allergies, asthma, or other medical conditions.