Windows are openings in walls, doors, or vehicles that allow the passage of light. Windows are important for a household's energy efficiency because they're how homes let heat and light in and out. Proper window placement and type are essential for energy-efficient building design making and it is a crucial part of the building envelope.

Head Jamb

The key horizontal components that are part of a window setup are the head jamb. The head jamb sits at the very top of the window frame and provides the window frame with structural support. The sash of the window rests against it. To maximize airtightness, the jambs can be fitted with jamb liners

The side jamb is the vertical part that holds firmly the window frame. It ensures the window doesn’t just swing to the other side when the window is closed.

Window Sills are among the best-known parts of a standard window. A window sill is part of the window trim, the decorative covering around the window's edge that protects where the window attaches to the wall and prevents drafts and moisture from getting into the home.

The head is simply the horizontal part of the window frame. It is attached to the head jamb. The head casing is the finished trim at the top of a window frame that covers the space between the top of the window frame and the wall.

Stiles is the main vertical components in the window frame of a sash that is found at the sides of a window.

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