What Size Should My Bathroom Ventilation Fan Be?

Air Quality

Everyday tasks like showering, bathing and shaving can put home-destructive humidity into the air in your Columbia home. There’s good news though—a straightforward bathroom ventilation fan can save you from distorted wood, mold growth, cracked drywall and other problems 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? Watts Electrical & Air Conditioning is here to answer your questions.

Today’s bathroom ventilation fans are small and sleek and they operate more quietly and efficiently than ever before. You’ll find a great range of choices, from classic fans that will get the job done to fans with integrated heat lamps, motion sensors and heat-exchanger ventilation that helps avoid warmed air from leaking through your ventilation. While you have a lot of bells and whistles to pick from, the most important aspect of your fan is whether or not it’s large 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 typical 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 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 follow HGTV’s guidance for bathrooms larger than 100 square feet – verify 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 unclear if your bathroom ventilation fan is the correct size, or you know it’s time for a new one, give the pros at Watts Electrical & Air Conditioning at call at 601-272-8497. We’re here to help you make sure you have a ventilation fan that will drive hard to care for your home and keep it comfy. 

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