WhisperCeiling 190 CFM Ceiling Surface Mount Bathroom Exhaust Fan, ENERGY STAR FV-20VQ3

This product features a totally enclosed condenser motor and a large, double suction blower wheel to quietly move air. A small wheel turning very fast will create more noise than a large wheel turning more slowly for a given airflow. This Whisper-ceiling bathroom fan uses a wide blower wheel that moves a large amount of air at reduced RPMs. The blower wheel is also designed to draw air in from both sides, which helps keep the noise down, as there is more area for the air to enter the wheel. In fact, it is quiet enough that you might not even know it's on.