The Broan® ZB110H ULTRA GREEN™ 110 CFM Ceiling Humidity Sensing Exhaust Bath Fan, delivers everything you wished for in a bath fan - premium ventilation to help reduce airborne pollutants, ease of installation, energy efficiency, consistent power, extremely quiet operation and multi-speed capability. ULTRASense™, Humidity Sensing Technology, means you no longer need to remember to turn the fan on when you shower. Unlike other competitive fans and wall controls that wait for a relative humidity set point to be reached, ULTRASense™ Humidity sensing multi-speed fans react to a quick rise in humidity to increase fan speed and clear the mirrors faster.