How closely a unit can maintain a given temperature. Today s units are quieter than older ones. Listen to the unit in the store before you buy. Adjustable louvers direct the air up, down, right and left. Some models have motorized louvers to blow cold air around the room.
Most models have the ability to switch from fresh air to recirculating.
Switch to outside air when you want to air out the room, switch to recirculate on the hottest days when the air conditioner is struggling to cool the room. Low profile models Some models hang below the window, minimizing the area of sunshine that they block. Some units have timers to turn on or off on a schedule. Set the unit to turn on before you come home from work. Remote Controls - Some have remote controls so you can activate from across the room.