A Guide to the Parts of a Window

Before you start shopping for the perfect window style to complement your home, learning the several parts that work together to create a functional and aesthetically pleasing window design is important. Replacing your windows enhances your home’s aesthetic, improves curb appeal, makes your home more energy efficient, and ensures effective temperature control. A guide to the parts of a window will help you work with manufacturers and installers to find the windows you need.

Parts of a Standard Window


The frame is the outermost part of the window, comprised of the head, jamb, and sill. It provides structure and support. It can be made of various materials such as wood, vinyl, aluminum, or fiberglass.


The glass is the most important part of the window as it provides visibility and insulation. It can be single-pane, double-pane, or triple-pane, depending on the level of insulation needed.


The sash is the movable part of the window that holds the glass. It can be a single or a double-hung sash; a double-sash consists of two parts that can move independently.

A Guide to the Parts of a Window


A jambliner is a strip on the sides of a window frame that provides a snug fit for the window sash.


The upper and lower rails comprise the horizontal piece of a window sash. The check rail, in the middle of the window, is where the upper sash’s bottom part meets the lower sash’s upper part.


Hardware includes all the components that allow the window to open and close, such as handles, hinges, lifts, and pulleys.

Locking Mechanism

The locking mechanism is used to secure the window in place when it is closed. It can be a latch, a lock, or a combination of both.

A Guide to the Parts of a Window

Weep Hole

Individual openings in the window sill that enable water or condensation to escape.


The major structural piece, either vertical or horizontal, that connects two or more windows together.


Grilles are decorative elements used to create a pattern or design on the glass. They can be made of wood, vinyl, or aluminum and come in various styles and colors.


The casing is the decorative molding that surrounds the window frame and provides a finished look. It covers the space between the window frame or jamb and the wall, can be made of wood, vinyl, or other materials, and comes in various styles and finishes.

A Guide to the Parts of a Window


Weatherstripping is a material that seals the gaps between the window frame and the sash, preventing drafts, air leaks, and moisture from entering your home.

Choose Replacement Windows with WindowFits

Understanding the different parts of a window can help you make an informed decision when choosing the right windows for your home or business. At WindowFits, our knowledgeable team can help you understand how every one of our windows works to help you choose the perfect ones for your home. We will work with you every step of the way to ensure you receive the window replacement you are looking for. Call us at (951) 677-2593 or click here for a FREE window installation quote!