What Size Should My Bathroom Ventilation Fan Be?

Average tasks like showering, bathing and shaving can put home-destructive humidity into the air in your Rochester home. There’s good news though—a modest bathroom ventilation fan can keep you from deformed wood, mold growth, damaged 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 right size? Are they as noiseless and energy efficient as they could be? Brogan Heating & AC Inc is here to answer your questions.

Today’s bathroom ventilation fans are small and sleek and they operate more quietly and effectively than ever before. You’ll find a large range of selections, from average fans that will get the job done to fans with fitted heat lamps, motion sensors and heat-exchanger ventilation that helps avoid warmed air from escaping through your ventilation. While you have a lot of bells and whistles to select from, the most important characteristic of your fan is whether or not it’s full-sized 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 exchange the air in a bathroom at least eight times an hour. With a standard 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 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 easy, you can heed HGTV’s tips 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 right size, or you know it’s time for a new one, give the professionals at Brogan Heating & AC Inc at call at 507-218-0088. We’re here to help you guarantee you have a ventilation fan that will run hard to protect your home and keep it comfy. 

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