# Window terms homeowners should know

Summary: Decode the basic window words that affect repair, replacement, comfort, and a written installation scope.  
Publisher: HomeFAQ  
Published: 2026-09-29  
Canonical: https://homefaq.com/windows/window-terms-homeowners-should-know/  
Tags: window terms, window replacement, window estimate

Window terms should help you compare what an installer is proposing. They should not pressure you into replacing a window before the frame, glass, and water-management problem are understood.

## Terms you may see in an estimate

**Sash:** The movable or fixed part that holds the glass. A sash-only repair or replacement is not the same as replacing the frame.

**Frame:** The fixed structure around the sash. Its condition matters when there are drafts, difficult operation, or water damage.

**Insert or retrofit replacement:** A new window installed within a sound existing frame. It can preserve trim but is not a fit for every opening.

**Full-frame replacement:** Removing and replacing the window and frame. It can allow inspection of the surrounding opening, but the scope is usually broader.

**Glazing:** The glass portion of the window. “Double-pane” means two panes of glass separated by a space; it does not describe the frame or installation quality.

**Low-E coating:** A thin glass coating intended to manage heat transfer. Ask how a proposed glass package fits your climate and exposure.

**U-factor:** A rating used to describe how readily a window transfers heat. Lower values generally mean less heat transfer, but compare the whole certified window—not glass alone.

**Air leakage:** The amount of air that passes through a closed product under test conditions. Installation gaps around the product are a separate concern.

**Flashing:** Material used around an opening to direct water outward. It is a critical scope item when replacing windows or repairing water damage.

**Weep holes:** Small drainage openings in many window systems. Keep them clear according to manufacturer instructions; do not seal them shut.

## Ask for a plain-language scope

Ask whether the work is an insert or full-frame project, what happens if damaged framing is found, and what flashing, air sealing, and trim work are included. Start with [Window repair or replacement](https://homefaq.com/windows/window-repair-or-replacement/) if you are still deciding whether replacement is needed.

## Sources

- [ENERGY STAR: Windows, Doors & Skylights](https://www.energystar.gov/products/windows_doors_skylights)