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It goes without saying that throughout the year the amount of sunlight in any given day is going to vary. The time of year and weather will have a strong influence on daily sunshine. Looking at the average amount of peak sunshine hours in a day during an entire year stretch is a valuable exercise when trying to determine the amount and type of solar panels you need to install to power your business or your home. 5 peak sun hours means that in Janney on average there are 5 hours a day where the sun is strong enough for solar panels to harness its energy. This number is less than the amount of total sunlight hours in a day because there are times during the day (ex. sunrise and sunset) where the sun is not strong enough to benefit solar panels.

The latitude of the location is important for measuring peak sun hours. The latitude determines how much overall sunlight there will be in a day. With a given latitude, time and date, one can accurately determine when sunrise and sunset will occur. Areas with latitudes closer to the equator will have a more consistent range of solar insolation throughout the year. Whereas areas closer to the poles will have a greater variance during the summer and winter months due to their higher latitudes.

The sun moves through the sky during the day, and changes positions in the sky throughout the year as the seasons change. A fixed solar panel remains fixed in position during this movement. So, although it is effective in capturing sunlight, a 1-axis or 2-axis panel can be more efficient. A 1-axis panel tracks the sun's movement throughout the day from sunrise to sunset. In addition to that, the 2-axis panel also accounts for the movement throughout the year.

The sunrise and sunset is very predictable every day, but things like cloud coverage and weather are less predictable and vary daily and annually. If a location that is usually very sunny experiences a huge increase in storms and cloud coverage in a given year than the average peak sun hours for that day or year will probably decrease. Tall objects such as trees and buildings can block out the sun during high solar insolation times, so be sure to strategically place your solar panels to get better efficiency.

In Janney the average yearly peak sun hours for a fixed tilt non-tracking solar panel mount is 5. 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 5.9 hours if you are using a 1-axis panel, and to 6.3 hours if you upgrade to a 2-axis solar panel.