What Size Should My Bathroom Ventilation Fan Be?

July 28, 2017

Average tasks like showering, bathing and shaving can put home-damaging humidity into the air in your Pflugerville home. There’s good news though—a straightforward bathroom ventilation fan can save you from warped wood, mold growth, damaged drywall and other problems associated 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? Evenaire Heating & Air Conditioning is here to answer your questions.

Today’s bathroom ventilation fans are small and smooth and they operate more quietly and effectively than ever before. You’ll find a hefty range of options, from average fans that will get the job done to fans with built-in heat lamps, motion sensors and heat-exchanger ventilation that helps prevent warmed air from leaking through your ventilation. While you have a lot of bells and whistles to select from, the most important aspect of your fan is whether or not it’s big enough to do its job.

Assessed 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 sufficient.

If you have a larger ceiling, the equation gets a little more complicated. 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 simple, you can follow HGTV’s tips for bathrooms larger than 100 square feet – establish 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 come to the point for a new one, give the pros at Evenaire Heating & Air Conditioning at call at 512-355-1482. We’re here to help you ensure you have a ventilation fan that will drive hard to protect your home and keep it cozy.