What Size Should My Bathroom Ventilation Fan Be?

July 28, 2017

Average tasks like showering, bathing and shaving can put home-destructive humidity into the air in your Laurel home. There’s good news however—a modest 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 quiet and energy efficient as they could be? H&C Heating and Cooling is here to answer your questions.

Today’s bathroom ventilation fans are small and sleek and they run more quietly and efficiently than ever before. You’ll find a great range of selections, from classic fans that will get the job done to fans with integrated heat lamps, motion sensors and heat-exchanger ventilation that helps avoid warmed air from escaping through your ventilation. While you can find a lot of bells and whistles to pick from, the most important aspect of your fan is whether or not it’s big 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 normal 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 adequate.

If you have a larger 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 advice for bathrooms larger than 100 square feet – establish 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 unclear if your bathroom ventilation fan is the right size, or you know it’s time for a new one, give the experts at H&C Heating and Cooling at call at 301-960-3247. We’re here to help you make sure you have a ventilation fan that will drive hard to guard your home and keep it comfortable.