What Is the Difference Between Three- & Four-Section Home Casement Windows?

Built In Window Units

• Casement windows are built in multiple-panel units. Each pane in a multiple-unit window is a separate window. Therefore, multiple-panel casement windows are sized to meet the customer's needs and architectural desires. Multi-panel casement window units can feature some panels that open, and others that are fixed.

Three-Section Casement Windows

• Three-section casement window units feature three glass panes. Typically, these windows are designed with a fixed casement window in the center and two crank-open casements on either end. These windows are custom built, so the individual panels' sizes are fully customizable. The three-panel unit can feature three windows that are all the same size, or two small crank-out casements on either end of a larger picture window.

Four-Section Casement Windows

• Four-section casement window units feature four individual casement windows built together into one frame. As the number of panels increases, the customer's options also increase. In most cases, these larger window units feature four casement windows that are all the same size. For some applications, and for the installer's convenience, four-panel casement windows are shipped as two sets of two casements. In this case, the builder frames and installs them next to each other to form the four-panel casement window in the customer's home.

Bay and Bow Windows

• As the number of panels in the casement window unit increases, customers have more options creating custom bay and bow windows. Bow windows usually are built from four-panel casement units. In a bow window, the four panels form a smooth arch that extends outward from the home. Bay windows -- which feature a seating area -- protrude much farther from the home. Trapezoid-shaped bay windows often are constructed from three or five casement panels. In a three-panel bay window, one casement forms each side of the window unit, and a larger fixed-pane picture window gives the homeowner an unobstructed view.