FreAire KN6391RGB Air Purifier: CADR, Noise, Coverage & Specs
Last verified: Aug 22, 2026
Aug 2026
Quick verdict
The FreAire KN6391RGB is best suited to rooms where published specs can be checked against your space where quiet minimum operation are priorities. Buyers should separately evaluate filter cost and maximum-speed noise before deciding.
Best for
- Low-noise minimum settings
Consider alternatives if
- You need a verified maximum-speed noise figure
- Filter replacement interval or cost is a deciding factor
Verified strengths
- 20 dB published minimum noise
- HEPA filtration (as published)
Verified limitations or missing information
- Maximum-speed noise is not in our sources
- Filter replacement interval is not verified
- Smoke CADR is not published
FreAire KN6391RGB overview
The FreAire KN6391RGB is an air purifier. It includes HEPA filtration and 20 dB minimum noise.
- Claimed coverage
- 1086 sq ft
- Minimum noise
- 20 dB
- Filter type
- HEPA
- Weight
- 3.06 lb
- Last verified
- Aug 22, 2026
FreAire KN6391RGB CADR and room size
Our recommended room size uses approximately 4.8 air changes per hour with an eight-foot ceiling. Manufacturer coverage figures may use a lower air-change rate and are shown separately.
FreAire KN6391RGB noise level
Published minimum noise is 20 dB.
Maximum-speed noise is not in our sources.
FreAire KN6391RGB filtration
Published filter type: HEPA.
Filter replacement interval is not verified in our sources.
FreAire KN6391RGB smart features
3-level high-efficiency filtration system, Filters smoke, pollen, pet dander, odors, and particles as small as 0.3 µm, RGB ambient lights, Sleep mode with 20 dB low noise
FreAire KN6391RGB specifications
- Manufacturer claimed coverage
- 1086 sq ft
- Minimum noise
- 20 dB
- Filter type
- HEPA
- Weight
- 3.06 lb
About FreAire air purifiers
FreAire models in this catalog are compared by CADR, recommended room size, noise, and filter type.
FreAire KN6391RGB comparisons
What is the CADR of the FreAire KN6391RGB?
CADR is not published for this model in our sources.
What room size is the FreAire KN6391RGB suitable for?
Recommended room size cannot be derived because CADR is missing.
How loud is the FreAire KN6391RGB?
Minimum reported noise: 20 dB.
Does the FreAire KN6391RGB have Wi-Fi?
No published Wi-Fi or app control in our sources.
What filter does the FreAire KN6391RGB use?
HEPA.
Methodology
Specifications are compiled from manufacturer documentation, product listings and other cited sources.
How we calculate recommended room size.
Sources
All air purifiers · FreAire air purifiers · Best air purifiers for allergies · Methodology