When installing photovoltaic modules, be aware that they generate maximum power when facing the sun directly. The fixed position which approximates this ideal over the course of the year, thus maximizing annual energy production, is facing due South (in the Northern Hemisphere) or due North (in the Southern Hemisphere) at the angle listed in the table in the next column. Note that these orientations are true,

At some installations, it may be cost-effective to adjust the tilt seasonally. At most latitudes, performance can be improved during the summer by using an angle flatter than the chart’s recommendation; conversely, a steeper angle can improve winter performance.

If modules are not cleaned regularly, it is recommended that they not be mounted at an angle flatter than 15”. Flatter angles cannot take ful1 advantage of the cleansing action of rainfall.

MODULE TILT ANGLE
Solar modules produce the most power when they are pointed directly at the sun. For installations where the solar modules are mounted to a permanent structure, the solar modules should be tilted for optimum winter performance. As a rule, if the system power production is adequate in the win ter, it will be satisfactory during the rest of the year. The module tilt angle is measured between the solar modules and the ground.