Solar Shading Analysis: Why Even Partial Shade Kills Your ROI

You think your roof gets plenty of sun. You stand in your yard at noon and see bright light on your roof.

But solar panels do not care about noon. They care about every hour from 6am to 6pm. And shade during peak hours destroys your return on investment.

Here is why shading matters more than you think.

How Solar Panels Handle Shade

Solar panels work in strings. When one panel is shaded, it reduces the output of the entire string. This is called the "weak link" effect.

Modern microinverters help by allowing each panel to operate independently. But shade is still shade. A shaded panel produces less energy regardless of the inverter type.

The Types of Shade That Matter

Tree shade: The worst kind. Trees grow. Shade that does not exist today will exist in five years. Evergreen trees are permanent problems. Deciduous trees create seasonal problems.

Building shade: Chimneys, neighboring buildings, and overhangs create fixed shade patterns. These do not change over time, which makes them predictable but still damaging.

Seasonal shade: The sun is lower in winter. Shade that disappears in summer returns in winter. Since solar production is already lower in winter, this compounds the problem.

How Much Shade Is Too Much?

• Under 10% shade: Acceptable. Most systems can handle this.
• 10-30% shade: Marginal. You will lose 15-25% of expected production.
• Over 30% shade: Poor candidate for solar. The system will not pay for itself.

The Cost of Ignoring Shade

A solar installer looking at your roof from the street may not see shade. Trees in the back yard, a neighbor's new addition, or a chimney on the other side of the roof can all create significant shading.

If you install a system without understanding your shade patterns, you could lose $5,000 to $15,000 in expected energy production over the life of the system.

Get a Satellite Shading Analysis

SolrScan uses satellite imagery to analyze shade patterns on your roof throughout the year. It shows you exactly which parts of your roof are shaded and when.

This takes 60 seconds and costs $19. It is the cheapest insurance you can buy before signing a $25,000 contract.

solrscan.com

Do not let shade turn your solar investment into a money loser.