Jalousie windows are made of multiple horizontal panels or louvers of glass and typically found on breezeways, doors and enclosed porches in warm climates, as well as on some mid-Century homes in cool climates. A hand crank opens and closes jalousie windows.
- A jalousie window has a number of identical "panes" of glass, typically a few inches high and more than 12 inches wide, depending upon the width of the window.
- Each piece or "slat" of glass is thicker than standard window glass and has smooth, rounded edges. Each has its own metal housing on the sides to keep the glass in place and to control movement.
- A crank on the inside of the window opens all of the slats simultaneously, much like horizontal window blinds. The glass opens out at an angle, one piece overlapping the next, so the window may be opened even during rain. Water runs down the angled panes and stays outside, except during extreme winds.
While jalousie windows offer a way to allow fresh air to enter even during rainy or somewhat windy weather, they are terribly inefficient compared to most modern standard windows. Since the glass panels close to resemble a look similar to roof shingles, a little air still flows through, so they are not a good choice for a heated room, although they may be fine for a breezeway or porch where cool temperatures do not matter. Over time, a pane of glass may fall out or break, calling for a replacement. Because these windows are not nearly as common as they were half a century ago, replacement glass for them must be special-ordered due to their thickness and smoothed edges. Due to the age of many jalousie windows, the aluminum hardware sometimes wears out or strips, calling for repairs.