What is a sone?

Sones are most commonly found in the rating of small fans  such as residential bathroom fans.

6 sones is the level that we typically speak at when seated around a conference table.

Keep in mind that noise is a subjective thing which varies depending on a person’s tolerance to such.

The following table relates sones to A-weighted decibels. Now, you ask, what is A-weighted decibels?

A-weighting decibels were originally intended only for the measurement of low-level sounds but are now commonly used for the measurement of environmental noise and industrial noise, as well as when assessing potential hearing damage and other noise health effects at all sound levels. In fact, the use of A-frequency-weighting is now mandated for all these measurements.

Here are some specifications from selected models

Airscape’s 2.5e is specified at 50 dBA but the test method is not defined.

Tamarack Technology data sheet on their 3400 CFM does not specify any noise level.

QuietCool’s Specs say ¬†48dB for their TRI-3.0 3200 CFM fan. Test method is not defined.

Invisco has released a video showing the sound of the 36 inch fan right next to it measured at about 63 dBA. Actual measurement of the sound once it is mounted high in the attic will be published when available. It is expected to be about 50 dBA. If you would like an update on that please email me at

Here is a table of sones and dB

sones dBA
0.5 30
1 40
2 50
3 56
4 60
5 63
6 66
7 68
8 70
9 72
10 73
11 75
16 80
22 85
32 90

Here are some real life examples:

Example of Noise source dB min More info
Boeing 737 or DC-9 aircraft at one nautical mile (6080 ft) before landing (97 dB); power mower (96 dB); motorcycle at 25 ft (90 dB). Newspaper press (97 dB). 90 4 times as loud as 70 dB. Likely damage 8 hr exp
Garbage disposal, dishwasher, average factory, freight train (at 15 meters). Car wash at 20 ft (89 dB); propeller plane flyover at 1000 ft (88 dB); diesel truck 40 mph at 50 ft (84 dB); diesel train at 45 mph at 100 ft (83 dB). Food blender (88 dB); milling machine (85 dB); garbage disposal (80 dB). 80 2 times as loud as 70 dB. Possible damage in 8 hr exposure.
Passenger car at 65 mph at 25 ft (77 dB); freeway at 50 ft from pavement edge 10 a.m. (76 dB). Living room music (76 dB); radio or TV-audio, vacuum cleaner (70 dB). 70 Arbitrary base of comparison. Upper 70s are annoyingly loud to some people.
Conversation in restaurant, office, background music, Air conditioning unit at 100 ft 60 Half as loud as 70 dB. Fairly quiet
Quiet suburb, conversation at home. Large electrical transformers at 100 ft 50 One-fourth as loud as 70 dB.
Library, bird calls (44 dB); lowest limit of urban ambient sound 40 One-eighth as loud as 70 dB.
Quiet rural area 30 One-sixteenth as loud as 70 dB. Very Quiet
Whisper, rustling leaves 20
Breathing 10 Barely audible

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