Available in single- and dual-grille combinations, Serenity series remove moisture from bathrooms of any size to help avoid such problems as mold and mildew growth and odor. Energy Star® 4.0-qualified fans are configurable to operate in any of 3 concurrent modes: continuous, humidity, and occupancy. With altitude correction feature, fans maintain ideal airflow up to 7,000 ft above sea level. Fan motor is typically installed in attic space, which minimizes noise.