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How Many Sones is a Quiet Bathroom Fan? 

Most people have heard a loud bathroom fan at some point in their lives, and realized how irritating that sort of racket is. In fact, you may be looking for a new fan in order to get a quieter one for your own bathroom. The problem is, practically every bathroom fan manufacturer claims that their products are "quiet," despite the fact that some are noticeably louder than others. How can you tell which fans are really quiet?

Look at the Sone Level of the Fans

What is the "sone level?" This is a measurement of loudness that is used just for fans. By comparing these levels, you can tell which bathroom fans out of a group of offerings will be quiet. You can also guesstimate just how loud one will be.

To get a good feel for this concept, imagine the volume of a quiet refrigerator in a quiet kitchen. That's one sone. Something twice that loud is two sones, and if the fan is three times as loud, it's three sones.

In Terms of Sones, What Qualifies as a Quiet Bathroom Fan?

The answer to this is slightly subjective because each person has a slightly different definition of "quiet." Some will be thinking of near silence, while others will consider a sound that's the same volume as a normal conversation to be acceptable.

That said, most consider a sone rating of 1.5-2 to be soft enough to be considered "quiet." This is still louder than that quiet refrigerator, but it will be very acceptable to most people.

If you have your eye on a fan with a higher rating on the sone scale, you might wonder just how loud it really is. It's often hard to imagine, say, a sound that's "four times louder" than a baseline. In order to help give you an idea, here are some sone estimates for other familiar sounds:

  • 4 sones – a TV at standard volume, three feet away
  • 4-16 sones – a passenger car 30 feet away
  • 16-32 sones – a major road 30 feet away

Another way to think of the sone scale is to compare it to the more-common decibel level description. Our handy sones scale conversion chart makes this easier. According to this, 2 sones is equivalent to 37.99 decibels, which is between the volume of a whisper and that of soft music.

Factors that Affect Perceived Sound Level

The measured sound level of a bathroom fan is a great guide, but it isn't the only factor involved in the actual perceived volume. That's because unlike a lab's testing room, your bathroom is subject to sounds from exterior sources. If your bathroom is next to a furnace or other source of fairly loud noise, a properly-running fan will usually seem quieter in comparison. On the other hand, if your bathroom typically has pin-drop silence, even a very quiet fan can seem louder.

Because of this, you should go for the quietest possible fan if there are no other noises competing against it. Then, you can be sure that you won't find the bathroom fan annoying. On the other hand, if the overall environment is fairly loud, you'll have more leeway when it comes to how many sones you can add without being bothered.

How Can You Tell the Sone Level of a Fan Without Buying It?

We list the expected sone level of each of our bathroom fans. This makes it easy to know how loud a fan will be before you buy it. Thanks to this listing, you can focus on the other features of the fan with no fear of loud surprises. 

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