What to Know Before Buying a Bathroom Exhaust Fan

Under unfavorable conditions, the moist air produced by baths and showers can be dangerous to your health and home. High humidity tends to create a perfect breeding ground for mildew and mold. And did you know that these interior pollutants trigger asthma, allergies and other respiratory problems?

Installing an exhaust fan in your home will help you control the humidity levels and remove odors from your bathroom.

But now, how easy is it for you to get an exhaust fan that can meet your needs? Well, it’s not easy at all.

Buying a Bathroom Exhaust Fan

With the extensive selection of bathroom exhaust fans in the market today, purchasing a new one for your home can be an overwhelming experience.

Luckily enough for you, we’ve put together this guide to help you decide which fan is best for your home.

Factors to Consider Before Buying a Bathroom Exhaust Fan

To settle for the best bathroom exhaust fan, consider the following factors.

Type of Exhaust Fan

There are 3 types of exhaust fans: window-mounted, ceiling mounted and inline fans. You, therefore, need to decide on the type to settle on first.

A ceiling-mounted exhaust fan is mounted on a false ceiling. It requires additional ducting to move the extracted air out of your bathroom.

These fans are best installed close or over the shower or bathtub area since it’s where excessive moisture levels are.

A window mounted exhaust fan also makes a great option. It is usually mounted over/on a window opening in the bathroom.

With this model, the air is immediately extracted outside, meaning there’s no need for additional ducting.

Inline/remote fans are models with a fan unit located in a remote area such as the attic. The fan is connected to an opening in the bathroom ceiling, usually covered by a grill.

These fans are normally used when homeowners wish to use only one fan to vent multiple rooms.

Size of Your Bathroom

You need to know the size of your bathroom if you want to get an exhaust that will adequately ventilate it. With the correct size, you’ll purchase a fan with the correct CFM. And since you want to ensure that you end up with a highly effective exhaust fan, taking the measurements won’t hurt, right?


This is perhaps the most important feature that you need to consider before paying for the fan. CFM simply stands for cubic feet per minute.

CFM rating indicates the amount of air the exhaust fan can move through in a minute. The higher the CFM, the more cubic ft. of air the fan can process and the better the ventilation potential.

The air in your bathroom gets saturated from the moisture created by the fixtures in it. The fixtures add to the humidity regardless of the size of your bathroom fan size. This influences the required CFM for the bathroom’s square footage.

This means that the more the faucets or water-consuming appliances in the bathroom, the higher the fan CFM will need to be.

The best bathroom fan should refresh the air in your bathroom completely 8 times in an hour or approximately once every 7.5 minutes.

So, how do you determine the right sized fan for your bathroom?

Approximate the CFM per square foot of the bathroom. For instance, if your bathroom is 50 square feet, you’ll need to get a bathroom exhaust fan rated for 50 CFM.

However, if your bathroom is larger than 100 square feet, add 50 CFM for each shower, bathtub, toilet and an additional 100 CPM capability for a whirlpool.

Special Features of the Fan

You also need to consider whether the fan you wish to buy boasts special features before paying for it. The more the features, the better.

Some fans have features that can help you save on energy, like the motion-sensing capability. This feature turns the fan off automatically once you leave the room.

Another important feature to consider in a bathroom exhaust fan is the humidity sensor. The sensor turns on/off the fan based on the humidity levels in your bathroom. It turns on when moisture is detected and off if, there’s no moisture.

The combination of a fan and light is common. However, if possible, ensure that you get one that comes with a low wattage night light to help you find your way around the room at night with ease.

Duct Size

For any bathroom exhaust fan to function effectively, it must have proper ducting. Therefore, you need to not only route it to the right place but also ensure that it is the right size to fit the fan’s duct connector.

To match the duct size, always measure the diameter of the duct that connects the fan. Ensure that the duct is sizeable enough to move air to and from the fan.


Sones is, in simple terms, the measure of the noise level. The perceived loudness of an exhaust fan is indicated in sones.

Sones is not measured in volume levels or specific decibels. Instead, it is an indication of the relative comfort level of everyone who hears the sound.

The higher the sone, the noisier the fan. A quiet exhaust fan is rated at 1.0 sones or less.

The best exhaust fan must offer 2 important features: quietness and the ability to remove moisture and odors. It’s always good to own a fan that sucks out most air at a lower noise cost.

However, you should expect to pay more for a quieter fan.


The amps rating of a fan is the measurement of the energy it uses to operate at the highest capacity. The higher the amperage, the more energy the fan requires and vice versa.


This indicates the amount of electrical force that the exhaust fan must be provided with to draw the correct amperage.


Look for the UL listing label before paying for the exhaust fan. This label acts as an indication that the unit has undergone rigorous performance testing. In short, it gives you peace of mind.

With the label, you are assured that the fan is certified to meet industry standards and that it’ll perform as promised. It is also an assurance that proper ventilation will be achieved to help you maximize indoor air quality.


An exhaust fan helps you to take care of your bathroom’s affair. It is important to choose a fan that will provide comfort and good air quality. Remember that you’ll spend a few minutes in the bathroom every day, and you don’t want to endanger your health or damage the walls of your bathroom with mold.(1)

After going through the guide, we can only hope that you are now well equipped for the shopping spree. It’s now time for you to head on to your favorite online/hardware store and get the bathroom exhaust fan of your choice.

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