What Size Should My Bathroom Ventilation Fan Be?

July 28, 2017

Average tasks like showering, bathing and shaving can put home-harming humidity into the air in your Cottonwood home. There’s good news still—a simple bathroom ventilation fan can protect you from warped 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 quiet and energy efficient as they could be? Connolly Electric & Mechanical is here to answer your questions.

Today’s bathroom ventilation fans are small and sleek and they run more quietly and economically than ever before. You’ll find a large range of choices, from average fans that will get the job done to fans with built-in heat lamps, motion sensors and heat-exchanger ventilation that helps avoid warmed air from escaping through your ventilation. While you have a lot of bells and whistles to select from, the most imperative feature of your fan is whether or not it’s big 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 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 almost as high as 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 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 tips for bathrooms larger than 100 square feet – establish your CFM requirements by increasing 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 Connolly Electric & Mechanical at call at 928-244-8840. We’re here to help you guarantee you have a ventilation fan that will run hard to care for your home and keep it comfortable.