What is the difference between True HEPA and HEPA-type filters?

True HEPA is a tested standard: the filter must capture at least 99.97 percent of particles at 0.3 microns, the hardest size to trap. HEPA-type, HEPA-like and 99 percent HEPA are marketing terms with no guaranteed rating — they may capture only 85 to 99 percent of larger particles and let far more fine particulate through. In short, True HEPA is a certified performance level; HEPA-type is a name that borrows the reputation without meeting the standard. For allergens and smoke, the difference is meaningful.

Is HEPA-type good enough for allergies?

Not as good as True HEPA. Allergens like fine pollen fragments, mold spores and pet dander include particles in the size range where True HEPA excels and HEPA-type falls short, so a True HEPA filter removes noticeably more of what triggers symptoms. HEPA-type will capture larger dust and some allergens, so it is better than no filter, but if allergies or asthma are the reason you are buying an air purifier, spend the modest extra for a certified True HEPA unit. Owner reviews from allergy sufferers consistently reflect that gap.

Does True HEPA remove smoke and fine particles?

Yes, far better than HEPA-type. Wildfire smoke and cooking smoke are dominated by very fine particles, including the 0.3-micron range True HEPA is specifically rated to capture at 99.97 percent. A HEPA-type filter lets substantially more of that fine particulate pass through. True HEPA does not remove gases and odors on its own, so for smoke a purifier that pairs True HEPA with an activated carbon stage handles both the particles and the smell. Match the filter to the pollutant.

What does 0.3 microns mean for HEPA filters?

0.3 microns is the most penetrating particle size — the size hardest for a filter to catch, because smaller and larger particles are actually trapped more easily by the filter's physics. True HEPA is rated at this worst-case size, so its 99.97 percent figure is a floor: it captures even more of the particles above and below 0.3 microns. That is why the standard uses this specific size. A HEPA-type filter carries no such tested guarantee at any size.

Is True HEPA worth the extra cost?

For allergies, asthma, pets or smoke, yes — the certified 99.97 percent capture is exactly what removes the fine allergens and particulate those situations involve, and the price premium over HEPA-type is usually small. If you only want to knock down visible dust in a low-need room, a HEPA-type filter costs a little less and does an adequate job. But given how modest the difference in price is, most buyers are better served choosing a genuine True HEPA unit and not second-guessing the label.

True HEPA vs HEPA-Type: What Is the Difference?

Written & researched by Derek Holt Home & Appliances Editor

Updated October 2026

Low-angle view of a person adjusting a floor-standing air purifier in a quiet living room, in soft overcast light

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True HEPA is a tested standard: the filter must capture at least 99.97 percent of airborne particles at 0.3 microns, the hardest size to trap. HEPA-type, HEPA-like and 99 percent HEPA are marketing labels with no certified rating that often capture far less fine particulate. Choose True HEPA if you are dealing with allergies, asthma, pets or smoke — the certified capture is what removes fine allergens and particles. A HEPA-type filter costs slightly less and is adequate only for knocking down coarse dust in a low-need room.

What's the difference?

The gap is a certified standard versus a borrowed name. To be called True HEPA, a filter must be tested to remove 99.97 percent of particles at 0.3 microns — a defined, verifiable performance level (the same class of standard used in cleanrooms and hospitals). Terms like HEPA-type, HEPA-like, and 99 percent HEPA carry no such guarantee; a manufacturer can use them for a looser filter that captures only larger particles at a lower rate. The words look similar on the box, but only one of them promises tested performance against the fine particulate that matters for health.

Low-angle view of a person adjusting a floor-standing air purifier in a quiet living room, in soft early-morning light

True HEPA vs HEPA-type at a glance

	True HEPA	HEPA-type
Capture standard	99.97% at 0.3 microns (tested)	No certified rating
Fine particles / smoke	Excellent	Weak — lets more through
Allergens (pollen, dander, spores)	Removes most	Removes some
Typical real capture	Meets or exceeds 99.97%	~85–99% of larger particles
Label names	True HEPA, Certified HEPA	HEPA-type, HEPA-like, 99% HEPA
Price	Slightly higher	Slightly lower
Best for	Allergies, asthma, pets, smoke	Coarse dust in low-need rooms

Wide view of a person adjusting a floor-standing air purifier in a quiet living room, in soft early-morning light

Which is better for allergies and smoke?

True HEPA, and it is the whole reason to care about the label. Allergens such as fine pollen fragments, mold spores and pet dander, along with wildfire and cooking smoke, are dominated by particles in the size range where True HEPA is specifically rated and HEPA-type falls short. Owner reviews from allergy and asthma sufferers consistently report better symptom relief from certified True HEPA units. One caveat: HEPA of any kind removes particles, not gases, so for smoke odor choose a purifier that pairs True HEPA with an activated carbon stage to handle the smell as well as the particulate.

Why 0.3 microns matters

0.3 microns is the most penetrating particle size — counterintuitively, the hardest for a filter to catch, because both smaller and larger particles are trapped more easily by the filter's physics. Rating True HEPA at this worst-case size means the 99.97 percent figure is effectively a floor: the filter captures even more of the particles above and below it. That is why the standard singles out 0.3 microns. A HEPA-type filter makes no tested claim at 0.3 microns or any other size, so its real-world performance against fine particles is unknown and generally lower.

Close-up detail of the material being worked in a air quality project, in warm evening lamplight

Which should you buy?

Buy a True HEPA air purifier if anyone in the home has allergies or asthma, if you have pets, or if you deal with smoke — the certified 99.97 percent capture is exactly what those situations demand, and the price premium over HEPA-type is usually small. A HEPA-type filter is acceptable only for knocking down coarse, visible dust in a low-need room on a tight budget. Given how little separates them on price, most buyers should choose genuine True HEPA and ignore the lookalike labels. Our picks come from aggregated owner reviews and expert consensus rather than first-hand testing — see how we rank.

Where to go next

Compare specific models in our best air purifiers roundup, plus the best air purifier for allergies and best air purifier for wildfire smoke. Related reading: how to replace an air purifier filter. All under the air quality hub.