What Size Should My Bathroom Ventilation Fan Be?

Ordinary tasks like showering, bathing and shaving can put home-harming humidity into the air in your Marshalltown home. There’s good news however—a modest bathroom ventilation fan can protect you from warped wood, mold growth, cracked drywall and other issues connected 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 noiseless and energy efficient as they could be? Kapaun & Brown Inc. is here to answer your questions.

Today’s bathroom ventilation fans are small and sleek and they work more quietly and effectively than ever before. You’ll find a great range of selections, from average fans that will get the job done to fans with built-in heat lamps, motion sensors and heat-exchanger ventilation that helps block warmed air from escaping through your ventilation. While you can find a lot of bells and whistles to select from, the most critical aspect of your fan is whether or not it’s large enough to do its job.

Rated 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 at least as high as 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 difficult. 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 easy, you can heed HGTV’s guidance for bathrooms larger than 100 square feet – determine your CFM requirements by adding 50 CFM for every toilet; 50 CFM for each shower, bath and combo; and 100 CFM for each whirlpool.

If you’re not sure if your bathroom ventilation fan is the proper size, or you know it’s the occasion for a new one, give the professionals at Kapaun & Brown Inc. at call at 641-812-2028. We’re here to help you guarantee you have a ventilation fan that will drive hard to care for your home and keep it comfy. 

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