Angle and Orientation: Efficiency Table
The "Orientation" of a solar array defines whether it is facing south, southeast, and so forth. Essentially, what part of the horizon the panels are facing. It's favorable in the northern hemisphere to have panels facing south. The closer to South you are, the better the system performance.
The "Angle" is whether the panels are flat or vertical, or anywhere in between. It benefits the system to have the panels roughly 15 degrees less than your latitude. In other words, in CT where latitude is about 38, it's beneficial to have the panels at about a 25 degree angle.
As demonstrated in the table, you can see what the difference between panels that are 30 and 15 degrees in angle will produce, comparatively.