How bathroom fans work

How Bathroom Fans Work

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If you are wondering what are those fans are doing in your bathroom, then you have found the right page. It’s time for you to know how bathroom fans work and appreciate their important function in keeping your bathroom well ventilated and your health risk-free.

What are bathroom fans for?

Going back to your first question, bathroom fans aren’t installed to keep you cool while showering or doing your other businesses. It is intended to remove the moisture and humidity that cause foul odors or mold buildup. Because your shower area is a damp place, it is prone to be a breeding ground for bacteria. So, the best way to maintain the air quality and cleanliness of your bathroom is to install ventilation systems like a bathroom or exhaust fan.

Today’s bathroom fans are more than just fans or rotor blades. Now, they are electrically powered with AC or DC motors that ensure consistent operation day in and out. Aside from this, they are quieter and efficient in exhausting humidity and improving airflow. Most manufacturers also make bathroom fans aesthetically pleasing, complementing wall decorations. Some even include a light bulb to add brightness to the room.

Aside from bathrooms, this type of exhaust fan also contributes in maintaining the air quality of the entire house. If all restrooms in your house have bathroom fans, the humid air or smell can be expelled outside the house in no time. Of course, the effectivity depends on how powerful they are.

In summary, here are the purposes of bathroom fans:

  • To remove moisture and humidity
  • To eliminate smelly bathroom odors and air pollutants
  • To prevent water vapor that accumulates on the walls and mirror
  • To improve the overall air quality of the bathroom and home

How bathroom fans work

The simplest way to explain the operation is to know the role of each part. Every bathroom fan has a motor, a fan, and a vent; these are essential parts that need to be present in a unit to guarantee successful ventilation. The motor needs an electric supply to power the fan. As the rotor blades spin, moisture is drawn up and is exhausted through the vent hood. This will continue as long as the bathroom fan is plugged in or turned on.

The effectivity of the fan depends on the power, which is rated in cubic feet per minute or CFM. This is the measurement of the airflow capacity of how much the fan can draw moisture from the room in a specified period of time. Thus, it means that the higher the CFM rating, the more air is exhausted and the faster the airflow is. So, if you have a big room, you should get a bathroom fan with high CFM rating.


As a general guideline, one CFM is equivalent to one square foot of the room. For a 100-square-foot bathroom, you should get a 100 CFM exhaust fan. For bathrooms with a standard toilet, bathtub, and shower, an additional 50 CFM is needed to ensure proper ventilation since these fixtures are always damp or wet. For this reason, purchasing a bathroom fan with the right size and specifications is crucial. If the power rating is too low for the size of the room, moisture and odor won’t be effectively eliminated.


The old-style exhaust fans in the bathrooms are noisy, yet they are not properly doing their jobs. Today, you will find that electrically powered fans are more effective. However, the thing about powerful motors is that they are still noisy. And if they are not noisy, it means that they are not exhausting air at all. That’s why manufacturers integrate such kinds of technology to minimize the sound the motor produce. The noise of a bathroom fan is measured in sones. A good one has an average rating of 1.5 to 2.5 sones. Anything that goes beyond that will be disturbing to the ears.

Installation options

This type of appliance comes in different shape and sizes. They can be mounted on the ceiling, walls, or installed inline. All have their own pros and cons in terms of aesthetic design and performance. Aside from this, some bathroom fans can either have a simple switch for turning on and off, or a timer, exhausting moisture after you take a shower.

About the Author Joe Borges