Five certifications matter when you’re shopping for an air purifier. The rest is marketing. CARB is mandatory in California. AHAM CADR tells you actual particle removal rate. True HEPA means H13+ per IEST. Energy Star means efficient. UL/ETL means it won’t start a fire.
CARB
California’s Air Resources Board certifies that an air cleaner emits no more than 0.050 ppm of ozone. Sale of non-certified cleaners is illegal in California.
Why it matters outside California: ozone is a respiratory irritant. Any purifier marketed as an “ionizer,” “ozone generator,” or using “activated oxygen” may emit meaningful ozone. CARB certification screens that class out. Check the CARB certified list before buying any air cleaner.
AHAM CADR
The Association of Home Appliance Manufacturers publishes Clean Air Delivery Rate figures for three pollutant classes: smoke, dust, and pollen. CADR = (particle removal efficiency) × (airflow in CFM).
CADR lets you compare purifiers directly. A purifier with CADR 200 cleans twice as fast as one with CADR 100 at the same room size, regardless of marketing claims.
Rule of thumb: CADR should be at least two-thirds of your room’s square footage at 8-foot ceilings. A 300 sq ft bedroom needs CADR ≥ 200. AHAM certification is voluntary; purifiers without it often underperform their quoted airflow numbers.
HEPA
HEPA is a classification standard. Per IEST-RP-CC001 (American) and EN 1822 (European):
- H10–H12: “Semi-HEPA” — filters 85–99.5% of 0.3 µm particles.
- H13: 99.95% at 0.3 µm. This is what you want.
- H14: 99.995% at 0.3 µm. Overkill for home use.
- U15–U17: ULPA — used in semiconductor fabs, not homes.
“True HEPA,” “HEPA-type,” and “HEPA-like” are marketing terms with no regulatory definition. Look at the H-class number on the actual filter, not the product marketing.
Energy Star
Means the purifier meets EPA efficiency thresholds at its rated CADR. It doesn’t tell you whether the CADR is good — just that whatever the unit achieves, it does so efficiently. Useful secondary signal: an Energy Star purifier is cheaper to run 24/7.
UL / ETL
Basic electrical safety. Any electrical appliance sold legally in the U.S. should carry one of these marks. Its absence is a red flag.
What’s NOT meaningful
- “Kills 99.9% of viruses” — lab conditions, not room conditions.
- “Hospital-grade” — no regulatory meaning in consumer products.
- “Ionizer,” “photocatalytic oxidation (PCO),” “UV-C” bolt-ons — frequently produce ozone, VOCs, or formaldehyde as byproducts.
- “Pet dander specialist,” “allergen focus” — these are HEPA filters with branding.
Where Vyana fits
Vyana isn’t a purifier. Purifiers recirculate the indoor air you already have through a filter. Ventilators exchange that air with outdoor air entirely. The two solve different problems.
Vyana monitors outdoor air quality continuously and only brings outdoor air in when the readings are clean. The filtration step on the way in uses an activated-charcoal MERV 8 filter sized to bring the most fresh air in the least time. Pollens are filtered out before the air reaches your rooms. You never breathe air with other pollutants because the system simply doesn’t open the intake when pollen is high.
For a home with high CO2 or VOC issues, no purifier can solve the problem because purifiers don’t exchange air. Dual Vyana is the right answer. For particulate-only issues (a single dusty room, allergy concern, wildfire backup), a CARB-certified HEPA purifier alongside Vyana covers both bases.
Frequently asked questions
Is CARB certification required outside California?
No, only for sales within California. But the CARB list is a free public database you can use as a safety filter regardless of where you live. If a purifier isn’t on it, ask why.
What CADR do I need for a 400 sq ft bedroom?
For four-air-changes-per-hour (the bedroom sleep standard), CADR ≥ 270. Two air changes (less aggressive) is CADR ≥ 135. Use the smoke CADR value because smoke is the tightest filtration test.
Is “True HEPA” a meaningful label?
No. Unregulated marketing language. Look at the H-class number (H13, H14) on the filter cartridge.
Are ionizing air purifiers safe?
Many emit ozone as a byproduct. Even CARB-certified ionizers add an irritant most people don’t need. Avoid ionizers when a mechanical-filter purifier delivers equivalent particle removal without the ozone.