What Size Should My Bathroom Ventilation Fan Be?

Average tasks like showering, bathing and shaving can put home-damaging humidity into the air in your Pocatello home. There’s good news though—a simple bathroom ventilation fan can save you from warped wood, mold growth, cracked drywall and other issues 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 quiet and energy efficient as they could be? Vogts Heating & Air 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 selections, from simple fans that will get the job done to fans with integrated 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 choose from, the most important feature 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 push, a bathroom ventilation fan should be able to swap out 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 adequate.

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 use HGTV’s guidance for bathrooms larger than 100 square feet – verify your CFM requirements by toting 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 the occasion for a new one, give the professionals at Vogts Heating & Air at call at 208-621-0129. We’re here to help you guarantee you have a ventilation fan that will work hard to protect your home and keep it comfortable. 

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