What Size Should My Bathroom Ventilation Fan Be? 07/28/2017Average tasks like showering, bathing and shaving can put home-harming humidity into the air in your Keokuk home. There’s good news however—a simple bathroom ventilation fan can save you from warped wood, mold growth, cracked 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? WM J Kraus & Son is here to answer your questions. Today’s bathroom ventilation fans are small and smooth and they operate more quietly and efficiently 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 avoid warmed air from leaking through your ventilation. While you can find 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 replace the air in a bathroom at least eight times an hour. With a normal 8-foot ceiling, your ventilation fan should have a CFM rating almost as high as the number of square feet in your bathroom. Therefore, if your bathroom is 5 feet by 8 feet, a CFM rating of 40 would be sufficient. If you have a higher 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 easy, you can heed 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 unclear if your bathroom ventilation fan is the correct size, or you know it’s the occasion for a new one, give the professionals at WM J Kraus & Son at call at 319-524-3714. We’re here to help you ensure you have a ventilation fan that will drive hard to protect your home and keep it comfy. You can even set up an appointment with us online if that’s the most straightforward for you.