Azimuth
Azimuth is the compass direction that solar panels face, measured clockwise in degrees from due north. Azimuth determines how a solar array is oriented relative to the sun's path across the sky, directly affecting how much of the available solar resource the array captures throughout the day.
Standard azimuth references:
- 0° = True North
- 90° = True East
- 180° = True South (optimal for northern hemisphere)
- 270° = True West
Optimal Azimuth for Solar
In the northern hemisphere, true south (180°) is the optimal azimuth for maximum annual energy production, because it faces the sun's path across the sky throughout the year.
Production relative to true south (northern hemisphere, approximate):
- 180° (South): 100% (reference)
- 135° or 225° (SE/SW): ~95%
- 90° or 270° (East/West): ~85–90%
- 45° or 315° (NE/NW): ~70–80%
- 0° (North): ~60–70%
In the southern hemisphere, the optimal azimuth is true north (0°).
Azimuth vs. Magnetic Compass
SolarScope uses true azimuth (relative to geographic north), not magnetic north. Magnetic declination — the difference between true north and magnetic north — varies by location and must be accounted for when using a magnetic compass in the field. In the western US, magnetic declination is typically 10–15° east, meaning a magnetic compass reading of 170° corresponds to approximately 155–160° true azimuth.
Practical Considerations
Most residential rooftops have fixed azimuth determined by the house orientation. Ground-mount systems can be oriented optimally. East-west split arrays (half east, half west) are increasingly popular for commercial flat roofs, providing a flatter daily production profile better matched to building load.