Glazing Performance
What is SHGC?
By Sheng Xu · 8 July 2026
AI-generated illustrative image. Not a product test, certification record or project evidence.
The Solar Heat Gain Coefficient (SHGC) measures how readily solar heat passes through an entire window or door system, including both the glass and frame. Expressed as a decimal between 0 and 1, a lower SHGC indicates less solar heat transmission, which is generally optimal for cooling-dominated climates, while a higher SHGC can be desirable in heating-dominated regions. This 'whole window value' is critical for NCC compliance and WERS ratings, influencing a building's overall energy performance and specification decisions.
Why it matters
Window and door decisions are rarely about one metric in isolation. Standards, glazing, frame selection, installation conditions and project documentation all need to work together before a system is selected for a real site.