Insulated Glass Unit (IGU)

Related terms

• Glazing

  The glass component of a window and the process of installing it. 'Single/double/triple glazing' refers to the number of glass panes.

• Spacer

  The bar separating the panes of an insulated glass unit. 'Warm-edge' spacers reduce edge heat loss and condensation.

• Jamb

  The vertical side members of a window or door frame that the unit is mounted within.

• Insert / Pocket Replacement

  Installing a new window into the existing frame without disturbing trim or siding. Faster and cheaper but slightly reduces glass area.

• Laminated Glass

  Two glass layers bonded to an interlayer that holds shards together when broken — used for security, sound, and impact-rated windows.

• Impact-Rated Window

  A window with laminated glass and reinforced framing tested to resist windborne debris, required in hurricane zones.

• Lite

  A glass panel within a door (e.g., 'half-lite', 'full-lite', or decorative entry lites).

• Hopper Window

  A window hinged at the bottom that tilts inward from the top. Common in basements for ventilation and egress in some configurations.