What SHGC means
SHGC, the solar heat gain coefficient, is the share of the sun's heat that gets through a window. Lower numbers block more heat.
Also called solar heat gain coefficient.
Where it matters on a window and door job
Hot climates want a low SHGC; cold climates may want more free solar heat on the south side. It is on the window label next to U-factor, and energy codes set limits by climate.
What the model code says
- The energy code defines SHGC as the ratio of solar heat gain entering through the fenestration to the incident solar radiation. (IRC 2021, Chapter 11)
Check which code edition your building department enforces for SHGC before you quote.
What it costs
Jobs that involve SHGC are priced in the window replacement cost guide: about $750 typical, usually $350 to $1,100. The guide shows its sources and what moves the price. The window replacement cost calculator prices a job line by line.
Work it out
- Free calculator: Window replacement cost calculator
- Cost guide: Window replacement cost
- Tools, templates and guides: Free window and door resources
Sources: 2021 International Residential Code, Chapter 11, Energy Efficiency (ICC). Checked October 9, 2026.