Choosing the Right Bathroom Exhaust Fan

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Comfort

Bathroom exhaust fans are an essential element to any bathroom - used properly, they help eliminate excess moisture to avoid mold buildup, odors, and foggy mirrors. And in most municipalities, they’re required by code.

Which option is best for your project? Consider these details and best practices.

Ceiling-mount or remote-mount bathroom fan?

Different situations call for various types of bathroom fans. Use this section to decide whether a ceiling-mount bathroom fan or a remote-mount bath fan is better for your application. Then, use the following section to determine the amount of airflow required for your applicable situation.

Can Remote-Mount Bathroom Fans Be Used on the First Floor?

Because there are often finished levels above, first-floor bathrooms can be a challenge to ventilate with vertically-routed ductwork.

When ductwork is routed horizontally between two levels of the home, it can be difficult to locate a remote-mounted fan indoors. However, the exterior exhaust fan offers a solution to this challenge with an exhaust fan that mounts on the exterior wall. 

The fan’s natural sound is kept outdoors, at a distance from the ceiling grille for quiet operation, and removes moist air from the space efficiently and quickly.

However, while this solution may work for some homes, others may utilize an exterior side wall vent. In this case, exhausting moist air under the roof line may not be the best course of action, as the bathroom air may partially drawn back up into the the roof line and cause an issue.

For this issue, we recommend using a remote-mount bathroom fan connected with an insulated duct to a gable end, through the roof, or however, it makes the most sense to the installer to exhaust moist air out of the home.

Application Renderings

PBW110 with Grille

An excellent alternative to a remote inline fan when space is an issue or direct venting to the outside is required. Ideal for homes, condominiums and apartment complexes. Comes with a 4" grille.

Reducing Noise

Even though a traditional ceiling-mount bathroom fan may be remarkably quiet, its noise still might feel intrusive to some homeowners.

Remote-mount bathroom fans eliminate the sound factor due to the placement of the fan at a greater distance from the bathroom.

Also, ceiling grilles with or without lights can be easily positioned over showers, whirlpool tubs, steam showers, toilets, and/or vanities and connected to the remote-mount exhaust fan.

Remote-mount bathroom fans range from 100 to 370 cfm of air and can be specified with or without a light. Their seamless grille makes for better aesthetics.

Application rendering of the pb110

PB110 bathroom fan with grille

The fan is a great option for getting humidity out of a space no matter how small. This petite configuration is perfect for your premium single bathroom application. Comes with a 4" grille.

Removing Moisture from Multiple Locations or Bathrooms with One Fan

Depending on Code and what the homeowner desires to see, homes with more than one bathroom may have one bath fan exhausting air from multiple bathrooms simultaneously.

The CVS remote-mount bath fans offer dual- or quad-port functionality to rid the space of humid air. Additionally, large bathrooms could use the extra ports to exhaust multiple areas of the room.

Application Renderings

CVS 400A Multi-port Exhaust Fan

A multi-port fan works the best for home spas because you can address exhaust in the areas where it is needed the most: the shower, toilet and, of course, your Jacuzzi tub.

What Size Bathroom Fan Do You Need?

If the bathroom is 100 square feet or smaller, Home Ventilating Institute (HVI) guidelines require 1 CFM per square foot of bathroom or a minimum of 50 CFM of fresh air flow. To find the square footage, multiply the length of the bath by the width. For proper airflow in typical installations (when duct losses aren’t calculated), use a 0.1" water column for ceiling-mount fans, and a 0.2" water column for correct fan selection.

If the bathroom is over 100 square feet, ventilation is calculated based on the fixtures in the bath. Allow 50 CFM for each standard toilet, shower, or tub. Whirlpool and jetted tubs are calculated at 100 CFM. Add up the CFMs for all fixtures and you will have calculated the total CFMs required.

Additional Bathroom Fan Considerations

A bathroom fan can only do its job if everyone in the home uses it, and not everyone remembers. Specifying a bathroom fan with a humidity sensor, such as the bathfan SC110-130-150H, or a bathroom fan with our humidity sensor accessory, eliminates the human factor by automatically turning the fan on when there is a rapid to moderate increase in humidity or when humidity rises above a user-adjustable set point.

The fan will shut off at a user-adjustable 5 to 60 minutes after humidity stabilizes and is below the set point. The bathfan Series has a plethora of features among its models, including some with an occupancy sensor. When motion is detected, the bathfan - already running continuously at the pre-set low speed - will increase to high speed. The fan will continue to run for 20 more minutes after the person exits the area.