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 New Castle home. There’s good news however—a simple bathroom ventilation fan can keep you from deformed wood, mold growth, cracked drywall and other issues associated 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 quiet and energy efficient as they could be? Central Heating & Plumbing is here to answer your questions.

Today’s bathroom ventilation fans are small and smooth and they operate more quietly and economically than ever before. You’ll find a large range of choices, from simple fans that will get the job done to fans with fitted heat lamps, motion sensors and heat-exchanger ventilation that helps prevent warmed air from getting out through your ventilation. While you have a lot of bells and whistles to select from, the most important feature 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 transfer, a bathroom ventilation fan should be able to exchange 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 almost as high as the number of square feet in your bathroom. So, if your bathroom is 5 feet by 8 feet, a CFM rating of 40 would be satisfactory.

If you have a larger 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 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 unsure if your bathroom ventilation fan is the proper size, or you know it’s time for a new one, give the professionals at Central Heating & Plumbing at call at 724-658-7111. We’re here to help you make sure you have a ventilation fan that will run hard to care for your home and keep it comfy. 

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