Tech Drive Very-Quiet 70 CFM, 2.0 Sone Bathroom Ventilation and Exhaust Fan (70CFM New Version)

How to choose your Bathroom Fan? What is a sone rating? Sones, or the sone rating, is a term used to describe sound levels. Lower sone ratings are found on quieter fans. Higher sone ratings indicate a louder bathroom fan. What is CFM? CFM (Cubic Feet per Minute) measures fan air movement. CFM increases as air movement increases. A higher CFM is best for a larger bathroom; a lower CFM may be adequate for smaller spaces. TD-BF-01 110CFM/1.0Sones. Ventilating for bathroom up to 110 Sq. Ft TD-BF-02 90CFM/0.8Sones. Ventilating for bathroom up to 90 Sq. Ft TD-BF-03 70CFM/2.0Sones. Ventilating for bathroom fan up to 75 Sq. Ft