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 Chicago home. There’s good news however—a straightforward bathroom ventilation fan can save you from warped wood, mold growth, damaged drywall and other issues 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 quiet and energy efficient as they could be? iTemp Heating and Air Conditioning is here to answer your questions. Today’s bathroom ventilation fans are small and modern and they work more quietly and efficiently than ever before. You’ll find a large range of choices, from average 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 getting out through your ventilation. While you have a lot of bells and whistles to choose from, the most important aspect of your fan is whether or not it’s large enough to do its job. Rated by the cubic feet per minute (CFM) of air they push, a bathroom ventilation fan should be able to replace 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 adequate. 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 simple, you can heed 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 unclear if your bathroom ventilation fan is the correct size, or you know it’s time for a new one, give the pros at iTemp Heating and Air Conditioning at call at 773-704-0640. We’re here to help you ensure you have a ventilation fan that will run hard to protect your home and keep it comfy. You can even arrange an appointment with us online if that’s the most straightforward for you.