True HEPA vs HEPA vs HEPA-Type: What the Labels Actually Mean
True HEPA vs HEPA vs HEPA-type explained: the US DOE 99.97% at 0.3 micron standard, EN 1822 H13 and H14 grades, marketing terms, and why CADR matters more.
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"True HEPA" and "HEPA" usually describe the same target: a filter that captures at least 99.97% of particles at 0.3 microns, the efficiency the US Department of Energy's HEPA standard requires. "True HEPA" is a marketing phrase, not a separate grade. "HEPA-type", "HEPA-like" and "HEPA-style" are the terms to be wary of; they usually mean the filter does not meet that efficiency. The European standard, EN 1822, grades filters H13 and H14 by their efficiency at the most penetrating particle size.
For a home purifier, though, the filter label matters less than the whole machine's clean air delivery rate (CADR). A HEPA filter in a purifier that leaks air around it, or with a weak fan, cleans a room slowly. The AHAM CADR, measured on the complete purifier, is the better guide.
The labels compared
| Label | What it means | Regulated? |
|---|---|---|
| HEPA (US) | At least 99.97% efficiency at 0.3 microns, the efficiency DOE requires of the HEPA filters it qualifies (DOE-STD-3020) | The DOE standard applies to DOE facilities; consumer use of the word is not policed the same way |
| True HEPA | Marketing for "meets the HEPA efficiency" | No separate grade |
| H13 (EN 1822) | At least 99.95% at the most penetrating particle size | European standard grade |
| H14 (EN 1822) | At least 99.995% at the most penetrating particle size | European standard grade |
| HEPA-type, HEPA-like, HEPA-style | Usually below HEPA efficiency | No |
| "HEPA-grade in Sleep Mode" | Meets the efficiency at low airflow only, under a stated test | Depends on the stated test |
Why 0.3 microns?
Filters catch particles in different ways depending on size. Large particles hit the fibers; very small ones wander into them through random motion. Particles around 0.1 to 0.3 microns are the hardest to catch, which is why HEPA efficiency is specified near that size. A filter that achieves 99.97% there does better on both larger and smaller particles. EN 1822 tests at the most penetrating particle size for each filter rather than a fixed 0.3 microns, which is one reason H13 and US HEPA are close but not identical.
How makers word it, and what to watch for
- Specific numbers are good. "Captures 99.97% of particles at 0.3 microns" (Coway, Levoit on several models) or "H13" states a claim you can hold the maker to.
- Conditions matter. Levoit's Core 300-P listing calls its filter "HEPA-grade while operating in Sleep Mode" under IEST RP-CC001.7. That ties the efficiency to low airflow; at higher speeds more particles may pass. It is an honest statement, but a narrower one than an unqualified HEPA claim.
- Different sizes, different numbers. Blueair cites 99.97% down to 0.1 microns for HEPASilent, and Shark cites 99.98% under IEST-RP-CC007 for its NeverChange line. These are makers' claims under named tests.
- "HEPA-type" with no number means you should assume it is not HEPA.
Why CADR beats the label
A filter's efficiency describes the media in a test rig. A purifier's CADR describes how fast the whole machine cleans a room: the filter, the fan and any gaps where air bypasses the filter. AHAM tests CADR on the complete purifier and publishes it in the AHAM Verifide directory. Two purifiers with "True HEPA" filters can have CADRs that differ by a factor of three. When you compare purifiers, compare CADR first. Our CADR guide explains how.
Sealing matters too
Some makers, including Dyson and IQAir, emphasize that the whole machine is sealed so air cannot leak around the filter. That is a real engineering point: a HEPA filter is only as good as the seal around it. It is also something AHAM's CADR test captures automatically, because leaks lower the measured clean air.
Do you need H13 or H14?
For a home, no. The difference between 99.95% and 99.995% at the hardest particle size matters in clean rooms and hospitals; in a living room, the number of air changes a purifier delivers matters far more. A purifier with a good HEPA filter and a high CADR outperforms one with an H14 filter and a weak fan.
Replacement filters and HEPA claims
Third-party replacement filters often say "True HEPA" or "H13". Their efficiency has not been checked against the purifier maker's specification, and a poor fit lets air bypass the filter. If you buy one, check that it seals in the housing. See our guide to replacing HEPA filters.
For compact HEPA units you can move between rooms, see the best portable HEPA purifiers.
Frequently asked questions
Is True HEPA better than HEPA?
No. "True HEPA" is a marketing term for a filter that meets the HEPA efficiency of 99.97% at 0.3 microns. It is not a separate or higher grade.
What does HEPA-type mean?
Usually that the filter does not meet HEPA efficiency. Terms like HEPA-type, HEPA-like and HEPA-style have no standard behind them.
What is the difference between H13 and H14 filters?
Under the European EN 1822 standard, H13 filters capture at least 99.95% at the most penetrating particle size and H14 at least 99.995%. For home purifiers, CADR matters more than the grade.
Is a HEPA filter the same as a HEPA air purifier?
No. A HEPA filter is one part; how fast the purifier cleans depends on its fan, its seals and its filter together, which is what the AHAM CADR measures.
Do HEPA filters remove viruses and smoke?
They capture particles across the size range that includes smoke and virus-carrying aerosols. Smoke gases and odors need activated carbon.
Are third-party HEPA replacement filters as good?
Sometimes, but their efficiency and fit have not been checked against the purifier maker's specification, and air that bypasses a loose filter is not cleaned.
Sources
- DOE Handbook: Nuclear Air Cleaning Handbook, Chapter 3, Filters for the Nuclear Industry, US Department of Energy
- Guide to Air Cleaners in the Home, US Environmental Protection Agency
- AHAM Verifide Directory: Certified Room Air Cleaners, Association of Home Appliance Manufacturers
- Air Filtration Standards, AHAM Verifide
- Levoit Core 300-P, Levoit
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