Cost lever
SHGC
solar heat gain coefficient · the summer number
How much of the sun's heat the window lets in, 0–1. Lower blocks more heat. In cooling-dominated North Carolina, this is the number you feel.
What it means for you
The one that matters most on a west-facing NC wall at 4pm. A low SHGC is why the room stays usable in July — worth more here than a slightly better U-factor.
Where you'll see it
Top-right box on the NFRC sticker, right next to U-factor.
Related terms
Defined by Marc Hanley
Verified against NFRC
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