What are Good Sone Ratings?   

Like other fans, bathroom exhaust fans have noise levels that are rated in terms of sones. These ratings are sometimes listed along with the other technical specifications of the fan, making it possible to compare them against each other. However, this listing is only truly useful if you understand just what level of noise to expect when you see the number.

What Are Good Sone Ratings?

The answer to this depends on what you're looking for in your fan. The quietest ones are rated at less than one sone, which is just a bit quieter than a whisper. There are also several models rated between 1.5 and 2 sones, or just a bit quieter than soft music. These are good sone ratings for residential bathroom fans.

However, you might not need your fan to be that quiet. You may prioritize the volume of air that it can exchange, or you might be placing it in an environment that is already quite loud. Then, you might think a good sone rating is quite a bit louder than those typically desired for residential installation.

What's the Difference Between Sones and Decibels?

One of the most important differences is the way the sone scale is set up. It is a very simple system, where the number serves as a straightforward multiplier. For example, three sones is three times louder than one sone. This makes it easier to imagine a certain sone level just by seeing the number listed.

Decibels, on the other hand, are calculated according to a formula that is more complex. While a sound 10 times more powerful than near-silence is 10dB, one that's 100 times more powerful is only 20dB. Meanwhile, a sound that's 1,000 times more powerful than near-silence is 30dB. This measurement method often makes it harder to imagine how loud a certain dB level will be.

Are Sones Always Important when Choosing a Fan?

This depends on the need for quietness in your bathroom fan. For most residential uses, the sone level will be very important. Nobody wants to hear a roaring industrial noise throughout the house every time the bathroom fan goes on.

In commercial applications, however, there may be no need for quiet beyond avoiding a truly deafening racket. Bathrooms in loud industrial installations are hardly going to be a source of disturbance if their fans aren't soft. Even when the surrounding area is quiet, many companies don't care much about bathroom fan noise as long as it is in an area where customers can't hear it. Therefore, some commercial fan makers don't even list the sone levels of their fans.

Some commercial situations are in a "crossover" situation. The bathroom may be used by customers, increasing the need for quiet operation, but the fan must also stand up to 12 or more hours of daily use. Then, a commercial fan is needed, but some attention must also be paid to noise levels. These fans are typically louder than the ones found in homes, but ideally, the sound won't be obnoxious either.

What Other Factors Should be Considered for Residential Bathroom Fans?

While a residential fan's placement on the sone scale has a lot to do with satisfaction, it isn't the only factor to keep in mind. It's also important to pay attention to the CFM, or cubic feet per minute, that the fan can move. This tells whether the fan will be powerful enough for its intended placement.

To ensure that the bathroom fan is strong enough to do its job, look at the CFM first. Then, choose the one with the lowest sone rating for the quietest possible operation.