What Size Should My Bathroom Ventilation Fan Be?

Air Quality

Average tasks like showering, bathing and shaving can put home-damaging humidity into the air in your Marietta home. There’s good news however—a straightforward bathroom ventilation fan can protect you from deformed 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 proper size? Are they as noiseless and energy efficient as they could be? Boyles Mechanical LLC is here to answer your questions.

Today’s bathroom ventilation fans are small and sleek and they run more quietly and economically than ever before. You’ll find a great range of options, from average fans that will get the job done to fans with fitted heat lamps, motion sensors and heat-exchanger ventilation that helps block warmed air from leaking through your ventilation. While there are a lot of bells and whistles to pick from, the most imperative aspect of your fan is whether or not it’s big enough to do its job.

Graded by the cubic feet per minute (CFM) of air they push, a bathroom ventilation fan should be able to swap out 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 almost 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 sufficient.

If you have a larger 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 easy, you can heed HGTV’s tips for bathrooms larger than 100 square feet – determine your CFM requirements by increasing 50 CFM for every toilet; 50 CFM for each shower, bath and combo; and 100 CFM for each whirlpool.

If you’re unsure if your bathroom ventilation fan is the correct size, or you know it’s time for a new one, give the pros at Boyles Mechanical LLC at call at 866-326-9537. We’re here to help you make sure you have a ventilation fan that will work hard to protect your home and keep it cozy. 

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