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 Marshalltown home. There’s good news however—a modest bathroom ventilation fan can keep you from distorted 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 noiseless and energy efficient as they could be? B & G HVAC is here to answer your questions. Today’s bathroom ventilation fans are small and modern and they operate more quietly and economically than ever before. You’ll find a great 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 getting out through your ventilation. While you can find a lot of bells and whistles to pick from, the most imperative characteristic 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 push, 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 at least 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 heed HGTV’s advice for bathrooms larger than 100 square feet – determine 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 right size, or you know it’s the occasion for a new one, give the pros at B & G HVAC at call at 641-752-3429. We’re here to help you make sure you have a ventilation fan that will work hard to guard your home and keep it cozy. You can even set up an appointment with us online if that’s the most straightforward for you.