Work out solar panel tilt angle instantly with clear inputs, formula shown and shareable results.
The rule of thumb for fixed panels is a tilt of about 0.9 times latitude for year-round output, reduced by roughly 23 degrees for summer and increased by about 29 degrees for winter. At 45 degrees latitude that means 40.5 degrees annually, 17 degrees for summer and 69.5 degrees for winter. Seasonal adjustment typically gains 5-10% over a fixed angle.
Annual optimum
tilt = 0.9 x latitude
Seasonal adjustment
summer: 0.9 x latitude - 23.5; winter: 0.9 x latitude + 29
No - output changes only a few percent within 10 degrees of optimum, which is why roof pitch is usually accepted as-is.
Because winter sun is low and days are short, so the steeper angle also sheds snow and captures more of a weaker resource.