What Size Should My Bathroom Ventilation Fan Be?

Ordinary tasks like showering, bathing and shaving can put home-destructive humidity into the air in your Murrieta home. There’s good news though—a modest bathroom ventilation fan can protect you from distorted wood, mold growth, cracked drywall and other trouble 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? Cool Air Solutions is here to answer your questions.

Today’s bathroom ventilation fans are small and smooth and they operate more quietly and economically than ever before. You’ll find a great range of selections, from simple fans that will get the job done to fans with built-in heat lamps, motion sensors and heat-exchanger ventilation that helps prevent warmed air from leaking through your ventilation. While you can find a lot of bells and whistles to choose from, the most critical characteristic 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 move, a bathroom ventilation fan should be able to swap out the air in a bathroom at least eight times an hour. With a typical 8-foot ceiling, your ventilation fan should have a CFM rating at least 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 taller 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 use 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 unsure if your bathroom ventilation fan is the right size, or you know it’s time for a new one, give the pros at Cool Air Solutions at call at 951-299-9853. We’re here to help you ensure you have a ventilation fan that will work hard to care for your home and keep it comfy. 

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