What does “True HEPA” actually mean?
“True HEPA” was coined to distinguish real HEPA filters from cheaper “HEPA-type” imitations. In practice, most products labeled “True HEPA” meet the HEPA 13 level: 99.95% efficiency at 0.3 microns, the most penetrating particle size (MPPS). It is a genuine HEPA filter, but it is not the highest grade available.What is HEPA 14?
HEPA 14 is a classification under the European standard EN 1822. A HEPA 14 filter must capture 99.995% of particles at 0.3 microns in certified testing. The SonoHealth AirPro uses a medical-grade HEPA 14 filter and captures 99.9% of particles down to 0.1 microns, the same filtration class used in hospital cleanrooms and surgical suites.HEPA 14 vs. True HEPA: side by side
| Grade | Efficiency at 0.3 microns | Common label | Particles passing through |
|---|---|---|---|
| HEPA-type / HEPA 11 | ~95% | “HEPA-type,” “99% HEPA” | 1 in 20 |
| HEPA 13 | 99.95% | “True HEPA,” “Medical HEPA” | 1 in 2,000 |
| HEPA 14 | 99.995% | “Medical-grade HEPA 14” | 1 in 20,000 |
Does the difference matter for allergies, asthma, and smoke?
For most everyday dust, the gap is small. It matters most for ultrafine particles, where wildfire smoke, diesel exhaust, and allergen fragments fall well below 1 micron. Higher efficiency at the MPPS means fewer of these breakthrough particles reach your airways over a day of use.An air purifier reduces airborne triggers and supports cleaner indoor air, but it is not a medical treatment and cannot cure allergies or asthma. The U.S. EPA notes filtration works best alongside removing pollutant sources and ventilating. See the EPA Guide to Air Cleaners in the Home.
Beware “HEPA-type” and “HEPA-like” filters
Labels such as “HEPA-type,” “HEPA-like,” or “99% HEPA” usually indicate a filter that does not meet true HEPA standards, often closer to HEPA 11 (~95%). If a purifier’s filter grade or EN 1822 rating is not stated, treat the claim with caution.Which does the SonoHealth AirPro use?
The AirPro uses a medical-grade HEPA 14 filter (EN 1822, 99.995% at 0.3 microns) with an antibacterial coating, backed by a pre-filter, activated carbon, and fully enclosed UV-C. It captures 99.9% of particles down to 0.1 microns, covers up to 1,200 sq ft, and runs ozone-free.Bottom line
“True HEPA” typically means HEPA 13. HEPA 14 is a verified step up, capturing 10 times fewer particles at the hardest-to-trap size. If you are buying a purifier for health reasons, look for a stated HEPA 14 / EN 1822 rating rather than “True HEPA” marketing alone.Related: HEPA 14 Filtration · HEPA 14 vs. HEPA 13 · Best HEPA 14 Air Purifier · AirPro vs. Competitors · AirPro Overview