A 1.5-sone bathroom fan produces a soft, comfortable hum. It is clearly audible but unobtrusive, roughly equal to the sound of a quiet, modern refrigerator running or a gentle whisper of air. It will easily operate in the background without drowning out a normal conversation.
Choosing the Right Sone Rating
1.5 – 2.0 sones → Quiet, comfortable level for most bathrooms. 3.0 sones or higher → Noticeably louder, best suited for utility rooms or spaces where noise is less of a concern.
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.
Bathroom fan sound levels are measured in sones: 4.0 sones is the sound of standard television operation; 3.0 sones is typical office noise; 1.0 sones is the sound of a refrigerator; and 0.5 sones is the sound of rustling leaves. For quiet bathroom ventilation the fan should be rated at 1.0 sones or less.
1.0 sone: A 1.0 sone rating is roughly equivalent to the sound of a refrigerator running. 2.0 sones: 2.0 sones is the noise level in a normal office workplace. 3.0 sones: A fan rated at 3.0 sones will be roughly as loud as a face-to-face conversation.
In exhaust fans choosing a fan with a sound rating at or below 1 sone will be very quiet. 1 to 2 sones will be heard and anything over 2.5 sones will be noticeable. Generally the sound level of the exhaust fan will be a major contributor of the cost.
We recommend the Panasonic Whisper Choice DC Pick-A-Flow Ceiling Bathroom Exhaust Fan as the overall best bathroom exhaust fan. It's extremely quiet and very effective at removing humidity. If you have a small bathroom, you can opt for the Homewerks 7141-50-G4 Bathroom Fan.
Most fans are rated from 50 to 110 CFM, but some models designed for large master bathrooms, rec rooms and home theaters can be rated even higher. Choose a fan that can ventilate at least 1 CFM per square foot of room. So, for an 80 square foot bathroom, select an 80 CFM fan.
A bathroom 50 square feet or smaller needs a 50-CFM fan. For bathrooms between 50 and 100 square feet, estimate approximately 1 CFM per square foot. If your bathroom is larger than 100 square feet, tally the CFM requirements for the individual fixtures to estimate your needs.
Sones are used to measure noise, such as fans, which includes kitchen fans, bathroom fans, and those found in your range hood. One sone is equal to about 1,000 Hz with a sound level about 40 decibels above a normal reference level.
And yet, despite the logic that in certain scenarios people may benefit from the added privacy noisy bathroom fans provide, a bathroom exhaust fan isn't supposed to be that noisy. (The noise level may have to do with the quality of the fan.
1.5 sones will be extremely quiet, it is comparable to the sound of a refrigerator running. What does 0.3 sones sound like?
It can't be too big so far as performance, but it can be too big so far as efficiency. Water only evaporates so fast, so once you reach a fan size that clears the vapor as fast as it evaporates you're only sucking more heat/ac out of your house and creating more noise by going larger.
The tissue test: Hold a square of toilet paper or tissue up to the fan grille while it's running. If the tissue sticks in place, your fan is pulling air. If it droops or falls, the suction isn't strong enough.
Airflow QuietAir QT 100T Extractor Fan
The quietest fan available complying with building regulations "installed performance" requirements when ducted. Suitable for toilets, en-suites and bathrooms; and you will hardly hear the fan running, even at night!
Fans that operate quietly, typically ranging from 25 dB(A) to 30 dB(A), help maintain the tranquility of your bathroom space.
65 dB is unusually loud for a range hood. From the dB conversion chart above, 65 dB is about 13 sones, while most vent hoods are between 6 to 8 sones.
Typically, bathroom exhaust fans have a lifespan of about 10 years, provided they receive proper care and maintenance. If you think you have a fan that's nearing the end of its functional life, read on to learn about the signs that indicate it's time for a replacement.
Keep your ceiling fans running efficiently with these simple steps: ✅ Dust the blades – Use a microfiber cloth or pillowcase to trap dust. ✅ Check for wobbling – Tighten screws and balance the blades if needed.
The right ventilation for your bathroom
The quietest ones are rated at less than one sone, which is like a whisper. There are also several models rated between 1.5 – 2 sones, or just a bit quieter than soft music. These are good sone ratings for residential bathroom fans.
3dB represents a doubling or halving of power. It's the smallest change most people can reliably hear, and it's exactly half the dynamic range between "quiet" and "normal" listening levels. Master this number, and you master gain staging.
Although an increase of 3 dB represents a doubling of the sound pressure, an increase of about 10 dB is required before the sound subjectively appears to be twice as loud. The smallest change we can hear is about 3 dB.