If you’re in the market for new windows, one of the many things you’ll have to decide on is the window’s configuration – in simple terms, how, or if, it opens and closes. As with most things in building there’s no one “right” choice, and each has certain advantages and disadvantages.

  • Fixed: A fixed window, also called a picture window, is one that doesn’t operate. As you’d expect, fixed windows are the least expensive configuration, and also the most energy efficient.

  • Sliding: Perhaps the most common of the operable window configurations is the sliding window, which consists of one fixed pane of glass that half the width of the window and a second, movable pane of glass of equal size that slides horizontally across and to the inside of the fixed pane. In larger sliding windows – typically those over about 8 feet in width – there will be a fixed pane in the middle combined with one sliding pane on either side that move horizontally toward the window’s center.

    Sliding windows are typically the most economical configuration. They have a handle and lock in the center or along one edge, along with a secondary security ventilation lock that allows you to open the window about 2 inches and then lock it in that position.

    Sliding windows are designated by which side opens, as viewed from the outside. “X” is used to designate the sliding portion of the window, and “O” for the fixed portion. Therefore an “X-O” window – the most common – will have the left side operable and the right side fixed from seen from outside. A large window with a fixed center pane and two side sliders would be an “X-O-X.”

    Double-Hung and Single-Hung: Double-hung windows open vertically, and both panes are operable – the lower pane moves up and to the inside of the upper pane, and the upper pane moves down and to the outside of the lower one. Double hung windows offer more ventilation options in that you can let air in from the top or the bottom of the window, and are also one of the more traditional styles of window. Single-hung windows, which duplicate the look of the double-hung at a lower cost, have an operable bottom pane that moves up and to the inside of the fixed upper pane. Both styles have a center handle and lock, and some also have a security ventilation lock.

  • Casement: A casement window works like a door, with hinges on one side and the lock and handle on the other. Casement windows, which are another traditional style, open outward by means of a crank handle. They have very good weatherstripping all around, and allow the entire window surface to be opened. On the down side, they are typically one of the more expensive configurations, and the outward-opening pane can present a potential hazard on lower-floor windows.

  • Awning: Typically considered a more contemporary style, awning windows have hinges on the two top or two bottom corners and open out – like a door that’s been turned on its side – with the latch on the side opposite the hinges. Awning windows only open out to an angle of about 30 degrees, which limits the ventilation area, and are most commonly seen paired with a larger fixed window above.

    All of these window configurations are available in wood, vinyl, and aluminum frame materials, and in a very wide variety of standard sizes for new construction or custom sizes for use in retrofit situations. The fixed windows can also be ordered in round, half-round, triangular, and many other shapes, and can be paired with operable configurations to give you virtually unlimited design possibilities.


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