GSU Solar PV Installers · Pattern B · Living Diagram

Sun Angle vs. Panel Tilt

Drag the sun across the sky and rotate the panel with the tilt slider. Watch the angle of incidence change and see live how much of the sun's energy actually reaches the cells. Find peak output — then see what a 10° error costs you in kilowatt-hours.

Why angle matters more than most installers realize

The cosine law of solar irradiance. A panel receives maximum energy when sunlight hits perpendicular (90°). At any other angle, output = cos(angle of incidence). At 30° off-axis you lose 13%. At 60° off-axis you lose 50%. The math is relentless.

Optimal tilt ≈ your latitude. In Eugene, OR (44°N), a fixed panel at 44° tilt faces the sun most squarely averaged across the year. In Phoenix (33°N), 33°. The rule is simple; the math behind it is the same cosine law.

Sun Elevation Angle: 45°

45°

Panel Tilt from Horizontal: 30°

30°

Panel Output vs. Theoretical Maximum

70%

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Angle of Incidence

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Output %

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kWh/day (400W panel)

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Annual Loss vs. Optimal

🥉 Bronze — 80% output achieved

🥈 Silver — 95% output achieved

🥇 Gold — Perfect alignment (99%+)

✦ Platinum — Low sun survived

Ask GENO: "What is the optimal tilt angle for solar panels in my state?" or "How much does shading one cell affect the whole panel?" — GENO AI Tutor, 32 languages, 24/7.