What Size Should My Bathroom Ventilation Fan Be?

July 28, 2017

Everyday tasks like showering, bathing and shaving can put home-damaging humidity into the air in your Rock Hill home. There’s good news still—a modest bathroom ventilation fan can save you from deformed wood, mold growth, damaged 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 proper size? Are they as soft and energy efficient as they could be? US Air Heating and Cooling is here to answer your questions.

Today’s bathroom ventilation fans are small and smooth and they operate more quietly and effectively than ever before. You’ll find a hefty range of options, from average fans that will get the job done to fans with built-in heat lamps, motion sensors and heat-exchanger ventilation that helps block warmed air from getting out through your ventilation. While you can find a lot of bells and whistles to pick from, the most critical characteristic of your fan is whether or not it’s full-sized enough to do its job.

Rated by the cubic feet per minute (CFM) of air they transfer, a bathroom ventilation fan should be able to swap out 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 about 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 adequate.

If you have a taller 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 – verify 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 come to the point for a new one, give the professionals at US Air Heating and Cooling at call at 803-220-0761. We’re here to help you make sure you have a ventilation fan that will run hard to guard your home and keep it comfy.