Sunlight is the fuel for all solar technologies, and the term solar resource refers to identifying how much of it is available in a given collector area. There are three main factors that affect a roof’s solar resource: the direction the roof is facing, shading, and roof pitch.
The most rudimentary analysis requires standing on your site with your arms up in a “Y” form and looking to see what obstructions there are in the field of vision between your arms. This basically represents the productive sun hours of 9:00 am to 3:00 pm. The tilt of the earth on its axis and our location north of the equator result in a specific sun path that changes throughout the year. The sun is at its highest point at noon on the Summer Solstice, or June 21st.