Short Answer
Solar Heat Gain Coefficient measures how much solar radiation enters through a window. The appropriate SHGC depends on climate, orientation and design goals.
Detailed Explanation
SHGC is a number between 0 and 1 that represents the fraction of solar radiation that passes through a window. A lower SHGC means less solar heat enters — which is desirable in cooling-dominated climates or on west-facing windows that get hot afternoon sun. A higher SHGC means more solar heat enters — which can be beneficial in heating-dominated climates or on south-facing windows where you want winter solar heat gain. In South Jersey's mixed climate, a moderate-to-low SHGC is typically recommended, with lower SHGC on west and south-facing windows to reduce summer cooling costs. The right SHGC depends on the home's orientation, shading, and HVAC system.
Why It Matters
SHGC affects cooling costs and comfort. Choosing windows with the right SHGC for each orientation can reduce energy costs and improve comfort.