What Size Should My Bathroom Ventilation Fan Be?

Ordinary tasks like showering, bathing and shaving can put home-harming humidity into the air in your Irvine home. There’s good news still—a modest bathroom ventilation fan can save you from deformed wood, mold growth, damaged drywall and other issues associated 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 noiseless and energy efficient as they could be? True Home Heating and Air Conditioning is here to answer your questions.

Today’s bathroom ventilation fans are small and sleek and they run more quietly and effectively than ever before. You’ll find a hefty range of options, from simple 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 there are a lot of bells and whistles to choose from, the most important characteristic of your fan is whether or not it’s full-sized enough to do its job.

Assessed 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 satisfactory.

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 straightforward, you can follow HGTV’s guidance for bathrooms larger than 100 square feet – determine your CFM requirements by adding 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 correct size, or you know it’s the occasion for a new one, give the professionals at True Home Heating and Air Conditioning at call at 949-258-7259. We’re here to help you guarantee you have a ventilation fan that will run hard to care for your home and keep it comfy. 

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