A hung window opens by sliding vertically, either just the bottom sash (single hung) or both the top and bottom sash (double hung). It's the classic, traditional window profile most people picture first, and it remains the most common style for a reason: it fits naturally into almost any room, doesn't project outward, so nothing to catch wind or interfere with screens, shutters, or window coverings on either side, and a double hung version lets you open from the top, bottom, or both at once to control airflow direction. Double hung windows also tilt inward for cleaning the outside pane from inside the house, useful on upper floors or anywhere exterior access is inconvenient.