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 Shelby home. There’s good news though—a modest bathroom ventilation fan can save you from distorted wood, mold growth, broken 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 right size? Are they as noiseless and energy efficient as they could be? Hopper Heating and Air is here to answer your questions.

Today’s bathroom ventilation fans are small and smooth and they run more quietly and economically than ever before. You’ll find a large range of options, from simple 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 leaking through your ventilation. While you can find a lot of bells and whistles to pick from, the most important feature 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 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 adequate.

If you have a larger 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 follow HGTV’s guidance for bathrooms larger than 100 square feet – verify 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 not sure if your bathroom ventilation fan is the right size, or you know it’s the occasion for a new one, give the pros at Hopper Heating and Air at call at 704-233-7363. We’re here to help you ensure you have a ventilation fan that will drive hard to protect your home and keep it comfortable.