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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.

The latitude at the equator of the earth is zero degrees. This is where sunlight strikes the earth most directly. Due to the earth's curved shape, sunlight hits at a various angles depending on location. As latitude increases, the further you are located from the equator and more variance you see in sunlight hours. The latitude of Altoona is 41.6.

Since a fixed solar panel is set in one position it is ideal to place it at an angle that will expose the panel to the most sunlight throughout the year. This angle is generally the same angle of your latitude which is 41.6 for Altoona. You do not need to strategically place a 1-axis or 2-axis panel as much as you do a fixed panel. A 1-axis panel follows the movement of the sun during the day. Additionally, a 2-axis panel also adjusts for the suns various positions in the sky throughout the year.

Looking at latitude, average peak sun hours and various data can obviously help when planning for your solar power needs. The one thing you can never fully account for is changing weather. Storms, rain, cloud coverage all have an impact on solar panel capabilities.

In Altoona the average yearly peak sun hours for a fixed tilt non-tracking solar panel mount is 4.5. 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 6.5 hours if you are using a 1-axis panel, and to 7 hours if you upgrade to a 2-axis solar panel.