What is Noise at usable speed?
dB level at the fan speed you'd run overnight.
Short answer
Ask for dB and CADR at the same speed setting.
Noise at usable speed when buying a air purifier
dB level at the fan speed you'd run overnight.
Why it matters: Quoted noise is on sleep mode, which often delivers a fraction of the CADR.
Look for: Ask for dB and CADR at the same speed setting.
Full Air Purifier buying guide