A vacuum cleaner is considered quiet when its maximum stated noise level stays at or below about 70 dB, while 71–75 dB is still comparatively quiet for normal household cleaning. Models around 76–80 dB are more typical, and anything above 80 dB becomes intrusive during a long session.
The decibel scale is logarithmic: an increase of 10 dB is commonly perceived as roughly twice as loud, so the difference between 65 dB and 75 dB is substantial even though both numbers appear close. A reduction of only 2–3 dB is audible but much less dramatic.
Compare figures measured at the same distance and power setting. A low-mode claim is not equivalent to the maximum level produced with a powered floorhead, and a quiet motor can still be accompanied by brush-roll whine, turbulent airflow or rattling tools.
The chart below shows the noise-level distribution of quiet vacuums.
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Are quiet vacuums less powerful than louder models?
Quiet vacuums are not necessarily less powerful than louder models. In our research, quiet models with published figures averaged around 180 AW, compared with about 150 AW for vacuums rated above 75 dB; both groups were close to 30 L/s of airflow and 20 kPa of suction pressure.
Noise depends on motor speed, fan shape, airflow turbulence, insulation, floorhead design and how well panels and tools resist vibration. A quieter machine can therefore maintain strong pickup, although maximum or boost mode may still raise the sound level and should be compared separately from the normal setting.