Anatomy of a Replacement Window

If you’ve never had your windows replaced before, knowing how the replacement process works will give you the confidence to make informed decisions as well as make sense of the window replacement options that will be offered to you. In this blog, Renewal by Andersen® of Houston gives you a closer look at the anatomy of a window.

Anatomy of a Replacement Window

Window Glass

Window glass, also known as glazing, occupies the largest area in any window and is considered as its most important part. Traditionally, windows are fitted with single-panel glazing. Since glass naturally conducts heat, these old windows allow heat transference, which results in heat loss during winter and heat gain during summer. The indoor heating and cooling systems compensate for the temperature difference, which results in higher energy consumption.

To minimize heat transference, choose replacement windows with dual-panel window glass. Eliminating contact between interior and exterior surfaces dramatically reduces heat transference, which helps lower your monthly energy consumption. All Renewal by Andersen replacement windows are fitted with High-Performance™ Low-E4® glass packages carefully engineered for maximum energy efficiency.


Sashes are the movable “frame” that holds the window glass. Depending on the window style, it can be a vertical or horizontal slide mechanism, or it can be swung open and closed. Picture windows and other “fixed” window styles do not have sashes, instead the window glass is installed directly on the frame. Modern replacement windows have grilles or muntins that are installed on or between the window glazing, instead of holding up smaller pieces of glass. Renewal by Andersen replacement windows feature sashes that can be tilted or removed for easy cleaning.


Window frames hold the entire window together. The sashes are attached to the frame while the frame itself is attached to the wall opening. The horizontal part at the top is called the head, the bottom is called the sill, and both vertical parts are called the jamb. The type of material used to build the frame is important. It should be able to hold the weight of the sashes, have enough insulation to prevent heat transference and be stable enough to withstand temperature extremes without warping. Our exclusive Fibrex® frames have all of these features.

To learn more about popular window styles, including double hung windows, call Renewal by Andersen of Houston today at (281) 547-6177. You can also fill out our contact form to schedule a free estimate. We serve many areas in and near Houston, TX.