Heat-Reflective Coated Glass: The Solar Regulator for Building Energy Efficiency

Heat-reflective coated glass applies a thin film of metal or metal oxide to the glass surface to reflect solar thermal radiation. It is an important energy-efficient material for buildings in hot climates.

Core Principle: Selective Spectral Response

• Moderate Transmission of Visible Light: Ensures indoor daylighting

• High Reflection of Near-Infrared Heat Radiation: Blocks 50%-70% of solar heat energy

• Low-Emissivity Characteristics for Far-Infrared Radiation: Some products also provide thermal insulation

Main Types and Processes

Key Performance Indicators

• Visible Light Transmittance (Tv): 10%-70%, determines daylighting and privacy

• Shading Coefficient (Sc): 0.20-0.70, lower value indicates better solar heat blocking

• Solar Reflectance (ρe): 15%-50%, core heat insulation indicator

• Thermal Transmittance (U-value/K-value): Monolithic approx. 5.0-5.7, IGU can be reduced to 1.8-3.0

Differences from Low-E Glass

• Core Function: Heat-reflective primarily for summer shading; Low-E primarily for winter insulation

• Spectral Characteristics: Heat-reflective reflects visible light + near-infrared; Low-E transmits visible light, reflects far-infrared

• Applicable Climate: Heat-reflective suitable for hot climates; Low-E suitable for cold climates

• Appearance: Heat-reflective has strong mirror-like effect, rich colors; Low-E has neutral, transparent appearance

Core Applications
Commercial building curtain walls, public building skylights, industrial plants, agricultural greenhouses, refrigerator display cases

Selection Considerations

• Prioritize low Sc values (≤0.35) for hot climates

• West-facing facades require higher shading performance

• Off-line coated products must be used in insulating glass units with coating facing the cavity

• Consider light pollution control requirements

Development Trends
Moving toward high transmission with high reflection balance, double-silver/triple-silver film systems, integrating with Low-E to create "shading-type Low-E," with more natural and muted colors to reduce light pollution.

Summary
Heat-reflective coated glass achieves solar heat regulation through optical thin film technology and is a key energy-efficient material for buildings in hot climate zones. Understanding its functional differences from Low-E glass and making scientific selections are essential for balancing energy efficiency and comfort.