igus

An insulated glazing unit (IGU) is a sealed assembly consisting of two or more glass panes separated by a spacer and encased by a hermetic seal. The space between panes is filled with air or an inert gas to reduce heat transfer, improving thermal performance and reducing energy use in buildings.

IGUs are available in double glazing and triple glazing configurations. Spacers, often aluminum, create a stable gap and house desiccants to reduce moisture. Edge seals protect the insulating space from air leakage, while coatings such as low-emissivity (Low-E) on surfaces reduce radiant heat transfer.

Performance is described by metrics such as the U-factor (thermal transmittance), Solar Heat Gain Coefficient (SHGC), and light transmittance. Gas fills like argon or krypton can boost insulation, and specialized coatings or gas fills improve sound attenuation.

Manufacturers and regulators follow standards such as the European EN 1279 series or ASTM specifications in the United States to assess gas leakage, edge seal integrity, moisture content, and overall performance of IGUs.

IGUs are manufactured by assembling glass panes, spacers, desiccants, and seals, often in automated lines. Proper installation is essential to prevent thermal bridging and moisture intrusion; damaged units typically require replacement rather than repair.

With proper selection and installation, IGUs can provide decades of service, commonly 20 to 30 years or more, depending on climate, usage, and maintenance. Condensation or fogging between panes indicates seal failure and may necessitate replacement.

IGUs are widely used in residential and commercial windows, curtain walls, skylights, and other glazing systems to improve energy efficiency and occupant comfort.