Trying to cut down on air conditioner use? If so, the 2155A window exhaust fan may just be the perfect cooling alternative. This 16-inch electrically reversible window fan pulls in cooler air from the outside while expelling warm air from within. Energy-EfficientThe 2155A costs just pennies a day to run and is much more energy-efficient than a traditional window, wall, or central AC unit.Patented Storm Guard FeatureThis allows you to close the window behind fan for safety and security during inclement weather or while you’re away.Super PowerfulThe Lasko 2155A is powerful enough to circulate the air in as many as three rooms.Easy OperationThe 2155A is incredibly easy to operate. The electrically reversible motor works with just a quick twist of the dial.