Stand in the spot where you are planning to position your solar panels. Using a compass, find south and then stand at the height of your proposed position, look from east to west to determine whether there are any obstructions, like buildings and trees, that can block sunlight during the depths of winter.

To accomplish this, it would also help to record the sunrise and sunset positions at various times of the year. You can use the Solar path calculator at Sun Earth Tools to give you all required data for your location.

The purpose of the survey is to confirm the absence of obstructions in the severest of winters, when there is little sunlight for the solar panels and every little bit of light is essential.

Obstacles to the sun should be avoided. If they cannot be controlled for or removed, another location should be sourced. Mounting the solar panels on a frame placed higher up may help, but if the system is not required to generate a lot of power during the winter, this may not be necessary. It is only vital to avoid obstacles that shade your solar panels if you need them to work at full power throughout the year.

It is best to consider the expectation of making future adjustments at the beginning of your solar electric system installation, before you have begun the install process. Since a solar system has a lifespan of over 25 years, it is essential to ensure that it functions for the entire period and that it can tolerate adjustments. Looking to the horizon, take note of trees and other plants, like hedges or bushes, that may grow taller, thereby affecting the solar system’s efficiency over time. A small shrub may grow into a considerable obstruction in the span of a few years.

Also, check for possible building works that may occur in the future and the impact these constructions would have on your solar electric system. Unforeseen shading may cause a reduction in the efficiency of your system.

Another factor to consider is the possibility of heavy mist or fog during the year, which can also jeopardize your solar array’s efficiency.