HEPA “certified” air purifiers—what it really means, and how to pick one.
HEPA is a filtration standard designed to capture very small particles. In everyday shopping, you’ll often see “True HEPA” or “HEPA-grade” (e.g., H13) used on air purifiers and replacement filters. This site explains the basics in plain English and shares popular, well-reviewed options on Amazon.
Quick checklist
When people say “HEPA certified,” they often mean one (or more) of the following:
1) True HEPA or HEPA-grade media
Look for “True HEPA” (99.97% @ 0.3µm) or HEPA grades like H13/H14 (often used in EU standards).
2) Independent performance programs
Examples include AHAM Verifide (CADR testing), ENERGY STAR (energy efficiency), and CARB (ozone safety).
3) Honest marketing
Avoid vague claims like “HEPA-type” unless the brand clearly states the filter’s performance.
What is HEPA?
HEPA stands for High-Efficiency Particulate Air. A true HEPA filter is designed to capture a very high percentage of airborne particles—especially fine dust, pollen, and smoke. The commonly cited benchmark is 99.97% capture of particles 0.3 microns in diameter in standardized tests.
Real homes have many variables (room layout, airflow, leakage, humidity), so the purifier’s real-world performance also depends on CADR, placement, and how often you run it.
Pick by room size (CADR)
As a rule of thumb, aim for multiple air changes per hour. Higher CADR generally cleans faster.
- Small rooms: bedrooms, offices
- Medium rooms: living rooms
- Large rooms: open-plan spaces
Decide what you’re filtering
Most units combine a pre-filter + HEPA media + activated carbon.
- Dust & allergens → HEPA
- Odors/VOCs → activated carbon
- Pet hair → good pre-filter
Look for credible programs
Third‑party testing can add confidence beyond marketing claims.
- AHAM Verifide (CADR)
- ENERGY STAR
- CARB / ozone safety
Want ideas? Head to Amazon Picks for popular models and quick links.