What Size Should My Bathroom Ventilation Fan Be? 07/28/2017Average tasks like showering, bathing and shaving can put home-damaging humidity into the air in your Scottsboro home. There’s good news however—a simple bathroom ventilation fan can keep you from distorted wood, mold growth, damaged drywall and other problems related 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? Southern Heating & Cooling Inc. is here to answer your questions. Today’s bathroom ventilation fans are small and modern and they run more quietly and effectively than ever before. You’ll find a large range of choices, from average 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 leaking through your ventilation. While there are a lot of bells and whistles to pick from, the most imperative characteristic of your fan is whether or not it’s full-sized 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 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 about 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 taller 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 – 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 not sure if your bathroom ventilation fan is the correct size, or you know it’s the occasion for a new one, give the professionals at Southern Heating & Cooling Inc. at call at 256-574-1300. We’re here to help you ensure you have a ventilation fan that will work hard to care for your home and keep it comfy. You can even arrange an appointment with us online if that’s easiest for you.