A Glossary of Window Terms – Do You Speak The Lingo?

Replacement window terms and definitions is a subject that can get some folks frustrated. Because the purchase of replacement windows is an important one, it doesn’t help much when a window supplier likes to use industry-related jargon.

Included here are some of the more commonly encountered window terms, and our picture too will help you to quicker identify the anatomy and various components that make up a window.

Many explanations are given in the sections of this guide, but here is a quick look at some of the more popular terms and definitions of windows:

• Airspace
  This term is the sealed gap between the windowpanes in double or triple paned windows. It can be filled with air or another gas such as Argon or Krypton to help with insulation and noise reduction. The airspace should be between ½ and ¾ inches thick or it will not work effectively.
• Desiccant
  This term is the name of any substance placed in the airspace between the glass windowpanes to absorb any moisture and prevent fogging.
• Energy Star
  A U.S government program which windows and other products can qualify for if they meet the standards of energy efficiency required.
• Insulating Glass (IG)
  This is another term for a dual pane or triple pane window.
• Low-E Glass
  This glass has an insulating coating which reduces the amount of heat flowing through a window, but does not affect daylight. Low-E glass can bounce back between 40% and 70% of the heat that would otherwise pass through.
• Muntins
  This term is for a set of bars, either horizontal or vertical, that divides up a large area of glass in a window into multiple smaller areas. Muntins are also known as grilles or windowpane dividers.
• Picture Window
  This term means the same as a non-operable, non-venting or fixed-frame window. That is a window that is designed not to open.
• Rough Opening
  This is the hole in the wall where a new window is installed.