(See all images) Tech drive ventilation fan

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 up to 75 Sq. FtTD-BF-04 80CFM/1.5Sones Ventilating for bathroom up to 85 Sq.FTTD-BF-05-L with LED light ventilating for bathroom up to 75 Sq.FT.TD-BF-06 70CFM 0.3Sones ventilating for bathroom up to 75 Sq.Ft TD-BF-07 with Humidity sensor ventilating up to 110 Sq.FtTD-BF-08-L with LED light ventilation for bathroom up to 85 Sq.FT