Bathroom and Kitchen are particularly prone to moisture problems caused by high humidity.This feeds mold, mildew, and even structural rot. Kitchens need ventilation for expelling steam and cooking odors. And to expel humid air before it has a chance to condense, every bathroom needs ventilation. Preparation 1. Determine CFM ratingThe term "CFM" is an acronym that stands for "cubic feet per minute," a term used to describe a fan's efficiency in terms of airflow. 2. Determine sound ratingSone: Measures of the sound the fan makes, typically from 0.5 (almost silent) to 4.0 (sounds like a normal...