18/05/2024 By admin Off

What is Insulating Glass Unit IGU?

An Insulating Glass Unit (IGU) is a building component composed of two or more glass panes separated by a spacer and sealed around the edges to form a single unit with an air or gas-filled space between the panes. This design significantly improves thermal and sound insulation compared to single-pane glass.

Key Components of an IGU

  1. Glass Panes: Usually made of float glass, which can be treated or coated for additional properties such as low-emissivity (low-E) for better thermal performance.
  2. Spacer: Positioned around the perimeter between the glass panes to maintain a uniform gap. The spacer often contains a desiccant to absorb moisture and prevent condensation.
  3. Sealants: Used to bond the spacer to the glass and to seal the edges of the unit, ensuring airtight and watertight integrity.
  4. Gas Fill: The space between the panes is often filled with inert gases like argon or krypton, which provide better insulation than air.

Fabrication Process

  1. Cutting and Washing Glass: Glass panes are cut to the required size and thoroughly cleaned.
  2. Spacer Preparation: Spacers are cut and bent to form a frame that fits around the glass edges. Desiccants are inserted into the spacers.
  3. Assembly: The spacer is placed between the glass panes, creating a sealed cavity.
  4. Primary Seal: A primary sealant is applied to ensure an initial bond between the spacer and the glass.
  5. Gas Filling: The cavity is filled with an inert gas to enhance insulation properties.
  6. Secondary Seal: A secondary, more robust sealant is applied around the edge of the unit for durability and strength.
  7. Quality Control: The finished IGUs undergo various tests to ensure they meet insulation and durability standards.

Benefits of IGUs

  • Thermal Insulation: IGUs significantly reduce heat transfer, maintaining indoor temperatures and reducing energy costs for heating and cooling.
  • Sound Insulation: The space between the panes acts as a buffer, reducing noise transmission from outside.
  • Condensation Prevention: The sealed unit with desiccant-filled spacers minimizes condensation within the panes.
  • UV Protection: Coated glass can block harmful UV rays, protecting interior furnishings from fading.
  • Enhanced Security: Multiple layers of glass provide better resistance to breakage and improve security.

Types of IGUs

  • Double-Glazed Units: Consist of two panes of glass with a spacer in between.
  • Triple-Glazed Units: Have three panes of glass and two spacers, offering even better insulation.
  • Low-E IGUs: Feature low-emissivity coatings on one or more glass surfaces to reflect heat and improve energy efficiency.
  • Tempered or Laminated Glass IGUs: Used for added safety and strength.


IGUs are widely used in:

  • Residential and commercial windows and doors.
  • Skylights.
  • Facades and curtain walls in high-rise buildings.
  • Conservatories and sunrooms.

Overall, IGUs are a crucial element in modern architecture, emphasizing energy efficiency, comfort, and sustainability.