What Size Should My Bathroom Ventilation Fan Be?

Ordinary tasks like showering, bathing and shaving can put home-damaging humidity into the air in your Kearney home. There’s good news still—a simple bathroom ventilation fan can keep you from deformed wood, mold growth, cracked drywall and other trouble 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 noiseless and energy efficient as they could be? Thurston Heating & Air Conditioning is here to answer your questions.

Today’s bathroom ventilation fans are small and modern and they run more quietly and efficiently than ever before. You’ll find a large range of options, 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 leaking through your ventilation. While you can find a lot of bells and whistles to choose from, the most imperative feature 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 move, a bathroom ventilation fan should be able to replace 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. Thus, 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 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 use HGTV’s guidance for bathrooms larger than 100 square feet – verify your CFM requirements by increasing 50 CFM for every toilet; 50 CFM for each shower, bath and combo; and 100 CFM for each whirlpool.

If you’re not sure if your bathroom ventilation fan is the proper size, or you know it’s the occasion for a new one, give the experts at Thurston Heating & Air Conditioning at call at 308-624-3485. We’re here to help you guarantee you have a ventilation fan that will drive hard to protect your home and keep it comfortable. 

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