If you are buying an air purifier to deal with allergens, smoke, or dander, the difference between these two is not cosmetic. A true HEPA certification is a measured result on a standard test. HEPA type is a phrase a marketing team picked because the real one is taken. For the same money you can almost always get a genuine certified filter, so there is rarely a reason to settle.
True HEPA filter
A filter certified to capture at least 99.97 percent of particles at 0.3 micrometers. The tightest pass size of any mainstream home filter.
HEPA type filter
A marketing term for filters that resemble HEPA but have not passed the certification test. Capture rates vary wildly between products.
The real tradeoffs
| Dimension | True HEPA filter | HEPA type filter |
|---|---|---|
| Capture performance | Guaranteed 99.97 percent at 0.3 micrometers. | Unverified. Can be much lower. |
| Certification | Independently tested and labeled. | No test required to use the term. |
| Allergen performance | Excellent on pollen, dander, and dust mite fragments. | Variable. Some work well, many do not. |
| Smoke and fine particles | Good on the particulate fraction of smoke. | Usually poor. |
| Price range | Mid tier, occasionally entry level. | Entry level, often suspiciously cheap. |
| Replacement cycle | Every six to twelve months under normal use. | Similar, but replacement value is uncertain. |
So which one should you buy
Pick True HEPA filter
Pick true HEPA if anyone in the home has allergies or asthma, or if you live near wildfire smoke or heavy traffic.
Pick HEPA type filter
Pick HEPA type only if budget is truly rock bottom, and accept that the performance may not meet the claim on the box.
See our picks in this category
Once you've decided which concept fits your life, our hand tested roundups cover the specific products we recommend:
Frequently asked
Frequently Asked Questions
What does 99.97 percent at 0.3 micrometers mean?
It is the minimum efficiency at the hardest particle size to capture. Smaller and larger particles are captured more efficiently than the rated size.
Is H13 better than true HEPA?
H13 is a European EN1822 rating that is roughly equivalent or slightly stricter than true HEPA. Either certification is reputable.
Does a carbon pre filter matter?
Yes, for odors and gases. HEPA alone does not capture odor molecules. A carbon layer handles cooking smells, smoke gas, and VOCs.
How often do I replace the filter?
Six to twelve months for most homes. Cut the interval in half if you have pets or wildfire smoke nearby.
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