10/17/2023
What Are the Different Parts of a Window? A Complete Guide to Window Anatomy
8 min read
You might be able to spot a window from a mile away, but are you familiar with the different parts of a window? From decorative window trims to internal components that keep out the elements, every piece of a window unit plays a vital role. Knowing the proper window part names is useful when communicating with installation specialists and ensures you know exactly what you’re paying for in a replacement window.
We’ve broken down the components in this complete guide to window anatomy, including the specific terms for the interior and exterior parts of a window.
Exterior Parts of a Window Frame
The window frame surrounds and supports the window pane and can be made of aluminum, fiberglass, wood or vinyl. Each part of the exterior frame is a distinct component of a window:
- Head: The head of a window is the horizontal top part of the frame, which helps to support the structure and maintain the window’s integrity.
- Sill: The window sill is the horizontal bottom piece of the window frame that serves as both a structural support and a barrier against moisture infiltration.
- Jamb: The jambs are the vertical sides of the window frame that provide stability and contain tracks or rails that let the windows open.
- Apron: The apron is a decorative molding that is installed below the windowsill. It adds an aesthetic touch while protecting the wall beneath the window from moisture.
- Weep Holes: Weep holes are small openings built into the bottom of metal and vinyl window frames. They allow precipitation that collects in the window tracks to drain off.
Interior Parts of a Window Sash
Your window sash is the movable part of the window that houses the pane of glass. But it’s much more than just the part that holds the glass. Here are the components of a window sash:
- Pane: The window pane is the piece, or pieces, of glass in your window.
- Window Rail: The horizontal part of the frame at the top and bottom of the sash is called a window rail. It contains grooves that hold the window panes.
- Spacers: Spacers separate and support the different panes of glass in a window. Window World of St. Louis windows use the Intercept™ warm-edge spacer system to provide superior insulation and extend the life of your windows.
- Sash Lock: This is the locking mechanism that prevents rattling and drafts and keeps your windows secure.
- Lift: The lift is the handle for lifting and lowering the sash.
- Weatherstripping: Weatherstripping is used to seal gaps and cracks where the window frame and sash meet. It provides an extra layer of energy efficiency and protection against the elements.
Additional Window Parts
A window is more than a frame and a pane. Here are some other window part names you should know:
- Casing: The casing (aka window trim) is the decorative molding that surrounds the exterior window frames. It seals gaps between the window frame and the wall to prevent drafts from entering your home.
- Mullion: A mullion is a vertical or horizontal structural piece that divides the frame into different sections. It creates the appearance of separate smaller windows within a larger window frame.
- Grilles: Grilles are decorative pieces that create a visually appealing grid pattern on the window. They can also provide additional security and protection.
- Fixed Panel: Also called the stationary or picture window panel, a fixed panel is an unmovable, non-operable glass pane that does not open or close. It is most commonly seen in single-hung windows.
Window Anatomy FAQs
What are the main parts of a window?
The main parts of a window are the frame (the fixed structure installed into the wall), the sash (the operable or non-operable section that holds the glass), and the glazing or pane (the glass itself).
What is the sliding part of a window called?
The sliding part of a window is called the sash. On double-hung windows, both the top and bottom sashes can slide up and down. On sliding windows, the sash moves horizontally.
What is the top of a window called?
The fixed, horizontal piece of the window frame at the very top is called the head or the head jamb.
What is the bottom part of a window called?
The fixed, horizontal piece of the window frame at the bottom is called the sill. The flat surface area on the inside of the home, which often sits on top of the sill, is called the stool or stool cap.
What is the area around a window called?
The finished area around a window is called the trim or casing. This decorative molding covers the space between the wall and the actual window frame on both the interior and exterior of your home.
What are the things on the side of windows called?
The vertical side parts of a window frame are called the jambs. The vertical side pieces of the decorative wood or vinyl around the frame are called the casing or trim.
What are the vertical and horizontal pieces of the sash called?
The vertical pieces of the sash frame are called stiles, and the horizontal pieces of the sash frame are called rails. The horizontal pieces where the upper and lower sashes meet are specifically called check rails.
What Makes a Window Energy Efficient?
Windows are so much more than just their parts. It’s important that they’re energy efficient. Here are some key terms about energy efficiency to help you select the most energy-saving windows for your needs!
- Low-E Glass: Low-E glass (short for low-emissivity glass) is a type of window glass that has been treated with a thin, invisible coating designed to filter the amount of UV light that enters your home. This coating helps reduce heat transfer and energy costs all year.
- Argon Gas: Argon gas is used as an insulator in double and triple-pane windows. Combined with Low-E glass, this colorless, odorless gas keeps the window closer to room temperature, helping eliminate drafts and increase energy efficiency.
- Intercept™ warm-edge spacer system: This spacer minimizes condensation and keeps the edges of glass windows warmer, creating a more comfortable temperature year-round.
Common Window Types
Windows play a crucial role in defining the character and functionality of a home. They allow in natural light, add beauty inside and out and affect your home’s energy efficiency. When it comes to selecting the right windows for your St. Louis home, it’s essential to know the most common window types and their distinguishing features. Explore what replacement window style is right for you:
- Double-Hung Windows: This classic window style features two vertically sliding sashes that open from both the top and bottom. This allows for improved airflow while maintaining a timeless and versatile appeal.
- Sliding Windows: Sliding windows have a space-saving design with a single moving sash that glides open horizontally. They’re easy to operate, provide unobstructed views and create a sleek, modern appearance.
- Casement Windows: Casement windows are hinged at the side and open outward (similar to a door) using a crank mechanism. They boast excellent ventilation, a tight seal when closed for energy efficiency and panoramic views when open.
- Bay & Bow Windows: Bay and bow windows extend toward the outside, creating a charming alcove or bay-like space. They’re popular for maximizing your living area and view, infusing more natural light into the room and adding architectural interest to your home’s exterior.
- Awning Windows: Awning windows are hinged at the top and open outward, which make them ideal for maintaining airflow in inclement weather without letting rain inside. Some options can hinge at the bottom and swing downward.
- Garden Windows: Garden windows extend outward from your home and often have multiple panes of glass. They’re perfect for plant lovers to display their herbs and allow ample natural light into the room.
- Custom Windows: Designed for unconventional shapes, sizes and architectural spaces, custom windows are tailor-made to your home when standard windows don’t cut it. Window World of St. Louis can craft the perfect window for your unique space.
Why Should St. Louis Homeowners Be Aware of the Correct Terminology?
Knowing the anatomy of a window gives St. Louis homeowners confidence in their window replacement decisions. This expertise paves the way for precise communication with window professionals so you avoid misleading sales tactics and make well-informed choices. A deeper grasp of the industry’s terminology promises a more rewarding and successful window replacement experience.
Tips for St. Louis Homeowners After Learning Window Terminology
For St. Louis homeowners considering window replacement, it’s important to go beyond just window terminology and recognize key signs you should replace your windows. These include rising energy costs, increased drafts, visible damage and condensation between panes. Minor issues may be repairable, but substantial damage might require a complete window replacement.
Preparing to consult with window replacement experts? When you do, be sure to request multiple quotes for price and service comparisons, inquire about warranties, explore financing options and seek clarity on what happens after purchasing. Gathering this information in advance can streamline finding the right windows for your St. Louis home, eliminating potential future hassles.
Upgrade for Premium Window Design
Window World of St. Louis offers beautifully crafted windows that deliver unparalleled strength, security, curb appeal and energy efficiency. When you’re ready to enhance your home’s windows, our window experts are here to review all the window terms and replacement benefits with you. Contact us today to request your free estimate.