Calculating the Optimal solar panel Angle
As a rule of thumb, solar panels should be more vertical during winter to gain most of the low winter sun, and more tilted during summer to maximize the output. Here two simple methods for calculating approximate solar panel angle according to your latitude.
The optimum tilt angle is calculated by adding 15 degrees to your latitude during winter, and subtracting 15 degrees from your latitude during summer. For instance, if your latitude is 34°, the optimum tilt angle for your solar panels during winter will be 34 + 15 = 49°. The summer optimum tilt angle on the other hand will be 34 – 15 = 19°.
This is an improvement of the general method that gives better results. In this method, the optimum tilt angle for solar panels during winter is calculated by multiplying the latitude by 0.9 and then adding 29°. In the above case example of a latitude of 34°, the tilt angle will be (34 * 0.9) + 29 = 59.6°. This angle is 10° steeper than in the general method but very effective at tapping the midday sun which is the hottest in the short winter days. For summer, the tilt angle is calculated by multiplying the latitude by 0.9 and subtracting 23.5°. In the above case example, this angle would be (34 * 0.9) – 23.5 = 7.1°. For optimum tilt angles during spring and fall, 2.5° is subtracted from the latitude.
