Understanding HEPA Filtration
HEPA (High-Efficiency Particulate Air) filters are the gold standard for air purification. True HEPA filters capture 99.97% of particles 0.3 microns or larger—including dust, pollen, pet dander, and many bacteria.
HEPA grades:
- H10-H12: HEPA-type (not true HEPA)
- H13: True HEPA (medical grade)
- H14: Ultra HEPA (hospital/cleanroom grade)
Look for H13 or "True HEPA" for genuine protection.
CADR: The Performance Metric
CADR (Clean Air Delivery Rate) measures how quickly a purifier cleans air, rated separately for smoke, dust, and pollen. Higher numbers mean faster cleaning.
To size correctly: Your room square footage × ceiling height = room cubic feet. Choose a purifier with combined CADR that can exchange your room's air 4-5 times per hour.
What HEPA Can't Catch
HEPA filters don't remove gases, odors, or VOCs (volatile organic compounds). For these, you need activated carbon filtration. Look for purifiers combining HEPA and substantial activated carbon filters for comprehensive protection.