What Size Should My Bathroom Ventilation Fan Be?

Air Quality

Average tasks like showering, bathing and shaving can put home-destructive humidity into the air in your Pella home. There’s good news though—a modest bathroom ventilation fan can keep you from distorted wood, mold growth, broken drywall and other issues related with a humid bathroom.

Even if you have ventilation fans in your bathrooms, do you know if they’re the correct size? Are they as soft and energy efficient as they could be? Van Haaften Plumbing & Heating is here to answer your questions.

Today’s bathroom ventilation fans are small and modern and they run more quietly and economically than ever before. You’ll find a large range of options, from classic fans that will get the job done to fans with built-in heat lamps, motion sensors and heat-exchanger ventilation that helps prevent warmed air from getting out through your ventilation. While there are a lot of bells and whistles to select from, the most imperative characteristic of your fan is whether or not it’s big enough to do its job.

Assessed by the cubic feet per minute (CFM) of air they move, a bathroom ventilation fan should be able to replace the air in a bathroom at least eight times an hour. With a normal 8-foot ceiling, your ventilation fan should have a CFM rating about the number of square feet in your bathroom. Thus, if your bathroom is 5 feet by 8 feet, a CFM rating of 40 would be satisfactory.

If you have a taller ceiling, the equation gets a little more complex. You’ll want to multiply the width of the room by its height and length, divide it by 60 and multiply by 8. Or, to keep it simple, you can follow HGTV’s guidance for bathrooms larger than 100 square feet – establish your CFM requirements by toting 50 CFM for every toilet; 50 CFM for each shower, bath and combo; and 100 CFM for each whirlpool.

If you’re unclear if your bathroom ventilation fan is the correct size, or you know it’s come to the point for a new one, give the professionals at Van Haaften Plumbing & Heating at call at 641-628-3621. We’re here to help you ensure you have a ventilation fan that will drive hard to guard your home and keep it comfortable. 

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