When Considering Shade, It Is Critical
Shading is the most confusing issue that most homeowners considering solar power face.
Modern photovoltaic (PV) solar panels, can tolerate a great deal more shade than their predecessors’ thanks to assistance from a new technology called a microinverter.
However, there is a limit. If there is too much shade, you will not be able to generate a return on your solar investment in a reasonable amount of time. However, there is a limit. If there is too much shade, you will not be able to generate a return on your solar investment in a reasonable amount of time.
Before we begin, however, I want to say that we love trees here at Sunbridge. Please remember that your trees protect your home from the scorching rays of the sun. This reduces your cooling bills and adds longevity to paint and roof life. Think carefully before you remove a tree in the interest of generating solar power. It can make sense, but a ground mounted system might also make sense. Talk to a trusted professional before you make a final decision.
Consider the Entire Year
This entire year of sun potential is often called your “Solar Window.”
Think about how low the sun sets on the horizon in late fall and early spring. This can make trees that seem insignificant in the summer, extremely significant in the winter. Here is what to look for:
Big trees that sit close to the home to east or west will reduce your solar production, but your roof could still work for a solar investment. Trees to the south are a much larger issue unless they are far enough away to prevent too much shade from falling on the home. Remember to take the entire year into consideration.
A professional, like Sunbridge, can use a tool called a Sun Eye or a parabolic mirror to completely analyze the shade that your roof will endure all year long. But you can get a feel for your potential using a handy trick.
Estimating Shade On Your Own
To get an extremely rough estimate of your solar window, you can use this little trick. Keep in mind that only a professional can actually estimate your solar window. Also, you must know your magnetic declination to find due south with a compass.
If you are sure that you know which direction is south, you can stand facing south and do this:
Stretch one of your arms upward overhead like this.
Take the other and point level to the ground. Now, this is important: don’t point to where you can see the sky – you will need to estimate where the horizon would be if there were no trees or hills or homes in the way.
Take your horizontal arm –the one on the bottom—and move it upward until you reach about 1/3 to ½ the distance to your top arm.
Trees in this area close to directly south could be problematic.
Now, sweep your arms to the east and west in a gentle arc like this to get a feel for what the rest of the day might look like all year long. A few trees between your hands should not be too much of a problem, especially if they lose their leaves in the winter. On the other hand, too many trees could be an issue. The closer any trees are to your top hand, the bigger your potential shading problems might be.
If the area between your arms resembles a forest filled with trees, solar may not work for you. Only a professional will be able to tell you for sure however using the latest solar technology,
When in doubt, get a free site survey from a trusted professional.