Insulating Glass

Insulating glass consists of two or more glass panes separated by a sealed air gap, utilizing a stationary gas layer to block heat transfer. It is the most fundamental energy-efficient product in modern architecture.

Core Structure

• Glass Panes: Can be float, tempered, Low-E, laminated, etc.

• Spacer Layer: Aluminum or stainless steel spacers create a cavity filled with dry air or inert gases (argon, etc.), thickness 6-20mm

• Sealing System: Dual-seal construction (butyl + polysulfide/silicone) with molecular sieve desiccant

Working Principle
The stationary gas layer (with thermal conductivity much lower than glass) cuts off heat transfer paths:

• Thermal Insulation: Prevents heat exchange between indoors and outdoors

• Condensation Resistance: Inner glass temperature remains closer to room temperature

• Basic Sound Insulation: Gas layer buffers sound wave propagation

Key Performance Indicators

• U-Value (Thermal Transmittance): Standard IGU 2.7-3.0 W/m²·K; Low-E IGU can reach as low as 1.4-1.8; Triple-glazed + double-silver Low-E + argon can achieve 0.6-0.8

• Shading Coefficient (Sc) / Solar Heat Gain Coefficient (SHGC): Clear IGU 0.80-0.85; Low-E IGU can be as low as 0.25-0.50

• Inert Gas Filling: Reduces thermal conductivity by an additional 10%-15%

• Weighted Sound Reduction Index (Rw): Standard IGU 30-35 dB; Composite with laminated glass can reach 38-42 dB

Main Types

• Double-Glazed: Basic type, cost-effective

• Triple-Glazed: Suitable for cold climate regions

• Low-E Insulating Glass: Mainstream choice for energy-efficient buildings

• Gas-Filled IGU: Filled with argon/krypton for enhanced insulation

• Multifunctional Composite IGU: Combines with laminated, ceramic frit, etc.

Core Applications
Building windows, curtain walls, skylights, refrigeration display cases, and other locations requiring energy efficiency and insulation.

Important Considerations

• Seal Integrity Determines Lifespan: Seal failure leads to gas ingress and condensation, rendering the unit useless

• Warm Edge Technology: Stainless steel or composite spacers reduce edge heat loss by 10%-15%

• Argon Retention Rate: Premium products achieve annual leakage rate <1%

Development Trends
Evolving toward vacuum-insulated composites, quadruple-glazed units (passive house standards), and smart integration (electrochromic/photovoltaic).

Insulating glass achieves energy efficiency through the physical principle of a stationary gas layer. Its quality directly determines a building's long-term energy consumption and indoor comfort.