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For fixed mounts, tilt equal to latitude maximizes annual energy production in the Northern Hemisphere. Adjust ±5° based on priority toward summer or winter output.
Optimal tilt ≈ Latitude (degrees)Summer optimal tilt is latitude minus 15°; winter optimal is latitude plus 15°. Adjustable mounts can capture 5–15% more annual energy than fixed at latitude alone.
Summer tilt = Latitude − 15°; Winter tilt = Latitude + 15°Convert roof pitch (rise/run) to degrees and compare to optimal tilt. Flat roofs use tilt racks; steep roofs may be within 10° of optimal without additional racking.
Angle (°) = arctan(Rise / Run)Updated: July 2026
Optimal fixed tilt is ~40°. A 9/12 pitch roof (37°) is nearly ideal. Summer adjustment to 25° gains ~3% summer output; winter adjustment to 55° helps snow shedding.
Optimal tilt is ~28° on tilt racks. Flat roof mounting at 10° (standard low-tilt) loses ~8% annual production vs optimal but saves racking cost and wind load.
Latitude-optimal tilt is 45°. A 12/12 pitch roof (45°) is perfect for winter production priority. Snow slides off above 40° tilt, maintaining production in January.
Panels must face south (Northern Hemisphere) regardless of roof pitch. A south-facing 30° roof outperforms an east-facing 45° roof even though the steeper angle is closer to optimal tilt.
Latitude minus 15° maximizes summer output but reduces winter harvest when days are shortest. Fixed systems at latitude balance seasonal production better in northern states.
Panel tilt angle significantly affects annual energy harvest. This calculator determines optimal fixed tilt from geographic latitude, compares roof pitch suitability, and provides seasonal adjustment angles for adjustable mounting systems.