If you are on the hunt for a quality bath fan with automatic moisture control, we have you covered!
In this guide, you will learn:
- Our #1 top pick for humidity sensing bath fans
- Tips on picking the best fan
- Frequently asked questions
- And more!
As a licensed inspector, I have seen numerous bathrooms with moisture and mold damage because the bathroom fan isn't even used.
Some people aren't even aware that the exhaust fan needs to be turned on when taking a shower — and for at least several minutes AFTER the shower. Bath fans with auto sensors are the perfect choice if you need the exhaust fan to automatically turn on...a "set it and forget it" mode.
With my experience in the home industry and spending numerous hours researching, I present my shortlist of the best bathroom exhaust fans with humidity sensors. Check out my comparison table below of the top picks or keep on reading for the detailed reviews and my buyer's guide. Let's get started!
| Image | Product | |||
|---|---|---|---|---|
Best Overall  | Best Overall | Panasonic WhisperSense
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| View on Amazon |
Best For Large Baths  | Best For Large Baths | Homewerks
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| View on Amazon |
Best For Small Baths  | Best For Small Baths | Delta BreezSlim
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| View on Amazon |
Best With Light, Sensor, And Timer  | Best With Light, Sensor, And Timer | Broan-NuTone Roomside
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| View on Amazon |
Best Budget | Best Budget | Delta BreezSignature
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| View on Amazon |
Best Controls  | Best Controls | Broan-NuTone QTXE110S
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| View on Amazon |
My Overall #1 Rated Pick
- Adjustable humidity sensor from 30% to 80%
- Countdown timer from 0.5-min to 60-min
- Pick fan speed (50/80/110) with tiny switch
- Very quiet at less than 0.3 sone
Our top choice for the best humidity sensing bathroom fan goes to the Panasonic WhisperSense because it includes an adjustable humidity sensor for automatic moisture control and can be set to 30% to 80% relative humidity. The WhisperSense is extremely quiet (rated at less than 0.3-Sone at 50-cfm) and there is even a tiny switch on the housing so you can choose between 50-cfm, 80-cfm, or 110-cfm fan speed!
6 Best Bathroom Exhaust Fans With Humidity Sensors
In a rush? Check out our top picks below! Keep scrolling to read the details on each pick and our buyer's guide.
- Panasonic FV-0511VQC1 WhisperSense DC 50/80/110-CFM (Best Overall Bathroom Exhaust Fan With Humidity Sensor)
- Homewerks 7136-02HW 140-CFM (Best Fan With Automatic Humidity Control For Large Bathrooms)
- Delta BreezSlim SLM70H 70-CFM (Best Humidity Sensing Exhaust Fan For Small Bathrooms)
- Broan-NuTone Roomside AER110SLW 110-CFM (Best Exhaust Fan With Light, Humidity Sensor, and Timer)
- Delta BreezSignature VFB25AEH 130-CFM (Best Budget Humidity Sensing Bathroom Fan)
- Broan-NuTone QTXE110S (Best Controls Extractor Fan With Auto Sensor)
What Is A Humidity Sensing Bathroom Fan?
A humidity sensing bathroom vent fan has a built-in sensor (humidistat) that responds to moisture in the air when taking a shower or bath.
Once the humidity reaches a particular level (such as 55% relative humidity) it activates a switch to turn on the bathroom fan automatically.
In an ideal world, people would turn on the bathroom fan when taking a shower or bath — and leave it on for 15-minutes afterwards. The 'leaving it on after' part is important so the bath fan can properly remove all of the moisture which takes several minutes (depending on the fan).
Read Also >> What Are The Best Humidity Sensing Exhaust Fans With Lights?
How Do Bathroom Fans With Humidity Sensors Work?
Humidity sensing fans turn on when someone uses the shower or bath and the humidity rises. The factory set point will usually be around 50% relative humidity but it is adjustable on some fans. When the moisture rises to the preset level, the fan will turn on. And when it drops below the preset level, the fan will turn off.
The most common way to turn the bath fan on is by toggling the wall switch. This will depend on the model but usually flipping the wall switch on ONCE will turn on the bath fan manually (regular mode). But if homeowners flip the switch ON and OFF and ON (one full cycle) then the humidity sensing mode will be enabled.
Some moisture sensing bath fans include small LED indicator lights on the housing so you can see if it is in regular or auto mode.
Read Also >> How To Replace A Bath Fan Without Attic Access?
How To Pick The Best Exhaust Fan With Humidity Sensor?
Here are a few things you should consider before buying a bathroom exhaust fan that are moisture sensing...
1. Sensor Adjustability
One of the most common complaints about humidity sensing bath fans is that they are too sensitive or not sensitive enough.
The humidity setting is a knob, dial, or switch on the fan housing that is accessible after the grille is removed. Homeowners can typically change the setting with their hand but may need a flathead screwdriver, it is easy to adjust it.
This doesn't mean that homeowners shouldn't buy a bathroom vent fan that isn't adjustable, but it is something to keep in mind.
2. CFM or Fan Speed
As with all bathroom fans, you need to size the fan speed correctly for your bathroom. The strength of bathroom fans is measured in CFM, or Cubic Feet per Minute. This metric will basically tell you how much air the fan can remove within one minute.
A general rule for sizing your fan is to measure the floor of your bathroom, and add 1 CFM per 1 square foot of floor space. For example, if your bathroom floor measures 80-sf, then you would want a bathroom fan with at least an 80-CFM rating.
I wrote a detailed guide on choosing the CFM or fan speed for bath fans here.
3. Housing Thickness Or Depth
It's a good idea to measure the height of the ceiling joists before you make your purchase.
If the fan is too tall or thick, then you can run into problems. As an example, if you buy a bathroom vent fan that has an 8-inch thick (height) housing, and if you have a home with 2" x 6" ceiling joists — it simply will not fit unless there is an attic above it.
Likewise, if you want to do a wall installation (vertical) then the bath fan housing can't be thicker than 4-inches if you have 2" x 4" wall studs.
4. Noise Levels
The noise level of a ventilation fan is measured in Sones which is a simple measurement of loudness. Noise level is really a personal preference but in general a bathroom exhaust fan that is 1-Sone or less is considered quiet. The loudest extractor fans are typically in the 3-4 Sone range.
5. Duct Size
As with all extractor fans, homeowners should consider the duct size.
Many new bathroom fans require a larger duct to the exterior such as 4-6 inches, but most older bathroom vent fans only use a 3-inch diameter duct.
Of course, you can always buy a 3" to 4" inch duct adapter (or it may come included) and still install the fan, but you won't get the full performance out of the new fan. It may also be louder than expected because of the smaller duct.
Read Also >> What Are The Best Humidity Sensing Panasonic Exhaust Fans?
How To Control An Automatic Bathroom Fan?
Homeowners should decide on how to control the bathroom exhaust fan before the purchase. This decision depends on who will be using the bathroom such as if it is for yourself, guests, or children. Here are a few options:
- Single Wall Switch: A single wall switch install is common and it works like this: you flip the wall switch once to turn on humidity sensing mode (auto) and toggle the switch twice to go into manual (high speed) mode. This can be problematic for house guests because they have no idea about how to go into manual mode.
- No Wall Switch: If switch toggling may be an issue, homeowners may want to wire the fan without a wall switch so that the humidity sensing mode is always on. Just to be clear, if the fan is wired without a wall switch, it can't turn on manually to only remove smells. This may be the best option for kids bathrooms or investment properties where there is concern about bathroom damage due to the occupants not using the fan.
- Two Switches: Another option is to have the bathroom fan wired to a separate switch if the fan also has a light so they can be operated separately. Remember, if you want to add an additional switch, you will have to add extra wiring.
- Motion Sensor: Sometimes humidity sensing fans include motion sensors. If someone just walks into the bathroom, the fan will turn on (usually at low speed). And then after a set period of time, like 10-minutes, the bathroom fan will turn off when it doesn't detect movement AND the humidity has dropped below the target level.
Read Also >> Our Ultimate Buyer's Guide To Bathroom Exhaust Fans
How To Clean The Moisture Sensor?
If the sensor gets dirty, then it simply won't work properly. It may be turning on and off at weird times (or not turning on at all) just because it's dirty.
The easiest way to clean the humidistat is to use a brush attachment on a vacuum. First you should clean the grille with the brush attachment because a dirty grille can also affect the functioning of the humidistat.
After cleaning the grille, remove the cover so that you have access to the sensor — and then thoroughly clean it. But don't use any harsh chemicals to clean the sensor!
Our Reviews of The Best Bathroom Exhaust Fans With Humidity Sensors
Pick #1: Panasonic FV-0511VQC1 WhisperSense DC 50/80/110-CFM
Best Overall Bathroom Exhaust Fan With Humidity Sensor
Our top overall pick goes to the Panasonic WhisperSense because it is a high quality exhaust fan that will automatically turn on and off to remove moisture.
The moisture sensor is fully adjustable with a wide range from 30% to 80% relative humidity.
The WhisperSense also has a built-in countdown timer from 0.5-min to 60-min to give you unparalleled control along with the sensor.
The WhisperSense has a premium variable speed motor which will speed up or slow down to maintain your desired CFM or fan speed. There is also a tiny switch on the housing that allows homeowners to choose the fan speed (between 50-cfm, 80-cfm, of 110-cfm) which offers great flexibility.
It is rated at less than 0.3-Sone on the 50-CFM speed setting which is extraordinarily quiet for a bathroom fan. The WhisperSense comes with the FlexZ-Fast bracket which will make the installation significantly easier.
Pick #2: Homewerks 7136-02HW 140-CFM
Best Fan With Automatic Humidity Control For Large Bathrooms
This Homewerks exhaust fan is our top picks for larger bathrooms up to around 140 square feet.
It features a moisture sensor that will turn on the bathroom fan with the relative humidity hits 60%. The sensor isn't adjustable, but this no-fuss option may be great for some homeowners.
There are two LED indicator lights with this Homewerks fan which shows if the fan is in humidity-mode or manual-mode. It is also pretty quiet at 1.0 sone and you may have trouble even hearing if it's on.
Pick #3: Delta BreezSlim SLM70H 70-CFM
Best Humidity Sensing Exhaust Fan For Small Bathrooms
The Delta BreezSlim (SLM70H) is a great bathroom fan that can be turned on/off based on humidity for smaller bathrooms up to around 70 square feet.
This 70-CFM bathroom fan has an automatic humidity sensing mode as well as a manual mode. For the manual you mode, you will have to override the humidistat by toggling your wall switch twice.
The BreezSlim is also a pretty compact exhaust fan, so it is good for 'retrofit' installations where you are replacing an older bath fan.
It is also designed to be used with 3-inch ducting which is usually what older bath fans use so you don't have to change the duct—saving a lot of work. In fact, since it is so much easier to install, that is why it is my top pick even though the humidity detector isn't adjustable.
Pick #4: Broan-NuTone Roomside AER110SLW 110-CFM
Best Exhaust Fan With Light, Humidity Sensor, and Timer
If you are looking for a humidity sensing bathroom exhaust fan that also has a light and timer — then the Broan-NuTone Roomside is a good bet.
The Roomside is rated at 110-cfm and it comes with an integrated LED light and humidity sensor.
And like the Panasonic WhisperSense, the Roomside also has a switch on the housing that allows you to adjust the humidity sensitivity.
By default it is 80% so if you don't think it is turning on when it should, you may need to adjust the humidity level lower.
One cool feature of the Roomside is that it comes with a built-in timer that is adjusted on the housing. This allows you to cycle the fan (toggle the switch) and then it will automatically turn off the fan without having to install a wall countdown timer.
Pick #5: Delta BreezSignature VFB25AEH 130-CFM
Best Budget Humidity Sensing Bathroom Fan
The BreezSignature is another great choice by Delta for a bathroom vent fan that is budget friendly. It includes a humidity sensor and a moisture sensor for auto control.
This fan is a bit more powerful than my other picks and it tops out at 130-cfm on high speed.
On lower speeds it will run at lower CFMs and the fan speed changes because it is a variable speed motor. The nice thing about variable speed motors is that they are more efficient and the speed can be adjusted to get the desired performance.
There is a so-called soft start when the bathroom exhaust fan turns on (a low CFM) and then it will eventually speed up.
A common issue with the old version of the BreezSignature is that the bathroom fan would be running constantly because of an overly sensitive humidistat. But the new version as of April 2021 includes an adjustable humidity sensor — change it from 50% to 80%.
Pick #6: Broan-NuTone QTXE110S
Best Controls Extractor Fan With Auto Sensor
The QTXE110S by Broan-NuTone is our pick for a humidity sensing bathroom exhaust fan with great control options.
This QTXE Series fan has a humidity sensor and a timer (similar to the Roomside fan).
The factory default setting is a 20-minutes delay, so it will turn off the fan once it drops below the humidity level (and 20-minutes elapse).
Both the humidity sensor and the timer are adjustable on the housing — you just need a screwdriver. The sensor can be adjusted between 50%-70% and the timer can be set to 5-60 minutes. The biggest difference between the Broan-Nutone Roomside and the QTXE110S is that the Roomside has a light and it is a bit louder.
The QXTE Series fan is extremely quiet and it comes in at only 0.7-sones on high (Roomside is 2 sones). The Roomside also has a circular shaped cover while the QTXE cover is square.
Our #1 Top Pick: Panasonic FV-0511VQC1 WhisperSense
Our overall top choice for the best humidity sensing bathroom fan goes to the WhisperSense by Panasonic. Here's why...
1. Adjustable Humidity Sensor
The humidistat is fully adjustable from a low of 30% and up to a high of 80% relative humidity. This wide range is larger than comparable exhaust fans and gives homeowners incredible control over the sensitivity.
2. Pick Your Own Fan Speed
Most extractor fans have fixed fan speeds or CFM but the WhisperSense is adjustable between 50-cfm, 80-cfm, or 110-cfm just be flipping a switch on the housing. To get to the speed selector switch, homeowners just have to remove the grille by squeezing the two spring clips on the side.
3. Adjustable Countdown Timer
The WhisperSense also comes with a built-in countdown timer that will turn off the vent fan automatically after a preset length.
It is fully adjustable from 0.5-min to 60-min. Homeowners can use this timer for automatic control to turn off the bath fan and it can be used TOGETHER with the humidistat. It will then turn off either when the humidity level drops below the set level or when the timer expires.
4. Quiet
This bathroom fan is extremely quiet and homeowners can make it even quieter by lowering the fan speed to 50-cfm from a higher level. The sone rating is less than 0.3-sone when on the 50-cfm fan speed.
