How Effective Is Your Bathroom Exhaust Fan?

How Effective is Your Bathroom Exhaust Fan?

Everyone loves a hot, steamy shower after a long day of work. Long, hot showers are the source of a lot of steam and moisture that gets trapped inside bathrooms for extended periods of time, which can lead to the possibility of mold growth. A lot of people don’t think about their bathroom exhaust fan and how this home product really makes the difference between having you conduct extra maintenance in your home or not. Great bathroom exhaust fans work to remove the excess moisture in bathrooms so that they stay ventilated enough to prevent mold build-up. But just because you can hear the fan does not mean that it’s functioning properly and productively removing the moisture from the room. Leading us to consider how effective is your bathroom exhaust fan?

Although bathroom exhaust fans are known for removing moisture, they also eliminate odors and improve the overall air quality inside of your home. Of course, it also removes humidity and moisture that could lead to structural damage, mold growth, or mildew that builds up over time as well. Look at your bathroom walls. If the paint is peeling from the ceiling and walls, that may mean that the fan isn’t sucking out the moisture in the air effectively enough, which would necessitate a replacement fan. 

Testing Your Bathroom Exhaust Fan 

One of the most common ways to test the suction of your bathroom fan is by taking a piece of toilet paper and putting it along the fan vent while the fan is on and running. If the fan suctions and holds up the piece of toilet paper, then that means that the fan is working correctly. If the piece of toilet paper does not stay attached to the fan, that means that the fan has not been sucking out any of the humidity in the bathroom. 

How to Choose the Right Bathroom Exhaust Fan 

Now that you know whether your exhaust fan is working or not, you may have to consider a replacement. Research has shown that it’s preferable to do regular maintenance on these fans because there is often the problem of inadequate airflow, high leakage rates, the inability to overcome status pressure or they may be in poor condition in general. No matter what the issue is, there are several factors to consider when choosing the best bathroom fan for you. 

Air Flow Rate 

Air Flow Rate
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According to the Home Ventilating Institute (HVI), for bathrooms under 100 square feet, a bathroom exhaust fan has to have a minimum of one cfm (cubic foot per minute) for every square foot of the bathroom. For example, if you have a 8’ x 10’ bathroom, then you will need 80 cfm minimum. For bathrooms that are larger than 100 square feet, the calculations are not based on the actual size of the room but on the number and type of fixtures in the bathroom. For the standard toilet, shower and bathtub the bathroom exhaust fan should have a coverage of 50 cfm, but if you have a whirlpool or a hot tub, it should have a coverage of 100 cfm. 

Fans can only remove the air in the bathroom at the rate that it can be replenished. The space that is in between the floor and the bathroom door is adequate in most cases but sometimes an additional air flow source has to be installed so that the fan is operating at its peak performance levels. This could come in the form of an additional grille on the bathroom door. 

Sound Level

Sound waves

When looking for a desired sound level of the bathroom fan that you are considering purchasing, it’s important to check for the HVI rating of the product. The HVI rating is just an indicator that the fan has undergone rigorous independent performance testing so that it meets industry specific standards. This rating also assures consumers that the product will perform the way that it promises and that there will be proper ventilation that will maximize your indoor air quality. If there is no HVI rating indicated, then there is a high chance that the fan will be noisy. A good sound rating is one that is 1.5 or lower. 

Fan Control 

Fan Control
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The HVI suggests that bathroom fans should run for at least 20 minutes after your shower so that you can be sure that the product is removing all of the excess humidity and moisture. Due to this, it’s preferable that the switch to turn on the bathroom fan is separate from the light switch because oftentimes they are both controlled by the same switch as a result of some bathroom installations. If this isn’t possible, then it’s also an option for the fan to run for a predetermined amount of time that’s controlled by a timer for after your showers. 


Bathroom exhaust fans are one of those home products that go under the radar until you notice that the walls of your bathroom are peeling and becoming moldy. To prevent it from getting this far,  you have to ensure that there is an adequate amount of airflow and ventilation in your bathroom. Before replacing or servicing your bathroom fan, always make sure to test its suction ability by performing the toilet paper test. It’s always better to have a product that actually does what it’s supposed to as opposed to just making a loud noise. 

Written by Julia Batista

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