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Peak sun hours is one of the most important criteria to examine when considering installing a solar power system. Peak sun hours are different than total sunlight hours in a day because the strength of the radiation of the sun varies throughout the day. For example, during sunrise and sunset the solar insolation from the sun is less powerful than at noon. For a moment of sunshine to be considered a peak sun hour the intensity needs to be at least 1 kilowatt per square meter. This means that a square meter of your solar panel should be receiving 1 kilowatt of energy from the sun. This number is used because it is an amount of light that allows a solar panel to produce output efficiently and not under perform due to lack of sunlight power.

If you’re using a fixed axis and fixed tilt solar panel, the ideal angle of the panel mount should be set at an angle equal to or close to the latitude of the location of the panel. Latitude is a valuable measurement to use when figuring how many daylight hours and the angle of the sun in the sky for your location. Since at locations with a higher latitude the sun will find itself at more variable angles in the sky throughout the year it is important to set the angle of the panel correctly and efficiently capture more peak sun hours. In the Northern Hemisphere the sun will be at lower angles in the Southern sky in the winter, and higher angles during the summer months, so the angle of the panel is crucial when trying to maximize output.

Throughout the day the sun obviously moves throughout the Antioch sky. The suns position in the sky also changes throughout the year with the seasons. A fixed solar panel does not accommodate for these changes. However, a 1-axis panel rotates and follows the sun’s path during the day. A 2-axis panel both follows the sun’s daily path as well as the seasonal differences

Peak sun hours are greatly affected by weather patterns. Cloud coverage is a huge factor in peak sun hours per day because heavy cloud coverage will diminish the power of the solar insolation. You can use historical climate data to estimate average cloud and weather coverage, but it will obviously vary slightly from year to year.

In Antioch the average yearly peak sun hours for a fixed tilt non-tracking solar panel mount is 4.2. This is for a fixed panel mounted at an angle that is equal to the latitude of the location for the entire year. The amount of peak sun hours increases to 6 hours if you are using a 1-axis panel, and to 6.1 hours if you upgrade to a 2-axis solar panel.