Ventilation is key in any bathroom. A properly-ventilated bathroom will help to circulate air and remove all excess moisture, preventing mildew and mold from appearing. Bathroom fans are a great way to keep smells from leaving the room, and they can be best matched with a timer switch. To calculate the ideal CFM (cubic feet per minute) rating for your bathroom fan, you'll need to know the square footage of your bathroom. Once you have that number, multiply it by 0.1 to get the minimum CFM rating you should be looking for in a bathroom fan. Ventilation is essential in any space where there's a potential for moisture buildup, so make sure your bathroom is well-ventilated to protect your investment.