Do My Solar Panels Need Washed?

Installing solar panels is one of the most popular eco-friendly ways for homeowners and businesses to save on electricity. The popularity of solar power has grown exponentially in the United States over the last decade and there is one question that we here at JTK continue to hear. “Do solar panels really need to be washed?”

The answer is, yes… but not always. So, let’s dig into the truth about whether solar panels need to be cleaned.

Solar panels are made up of special materials (usually silicon) that can take in sunlight and turn it into electricity. At a very basic level, when sunlight hits the panel, it knocks tiny particles called electrons loose. Those electrons then start moving, and that movement creates electricity. Think of it like this: sunlight hits the panel, the electrons get excited, they flow through wires and create usable electricity to power a home, business, or anything that runs on electricity.

So, what happens when dirt, dust, pollen, and many other forms of growth and debris, build up on a solar panel/system over time? The buildup decreases the amount of light absorption for that panel/system and lowers its efficiency. Every bit of decrease in efficiency means a decrease in end user savings on their electricity! This means that there are many cases where washing a solar system is absolutely necessary to maximize the production and savings.

Environmental Factors That Affect Dirt Buildup

The location of a solar system is the greatest factors in determining whether a solar system will need to be washed. Consider how different settings produce different kinds of soiling. In rural areas, solar panels may get covered with dust from fields, farming, and gravel roads. In suburban areas, solar panels may have buildups of pollen, tree sap, or bird droppings. And in Urban areas, smog, air pollution, road dirt, and construction dust are constantly in the air and settling on solar panels.

Geographical areas and climates also play a part in the equation. Dirt may not build up on solar nearly as quickly in very rainy areas. Dry and hot climates lead to dust and pollen getting baked onto solar panels. And in very humid areas, mold, mildew, lichen, and algae often grow on solar panels, sometimes at rapid rates. Where we are located, here in Southeastern Pennsylvania, we are most often cleaning solar panels in rural settings where dirt and grime has built up from barn fans, field work, and unpaved driveways. We don’t see much mold, mildew, or lichen in our area due to our climate.

How To Know When Solar Cleaning is Needed

One of the most common questions we get asked about solar cleaning is, “How often do you need to clean solar?” and “How do I know if my solar needs cleaned?”

The answers to both of those questions are the same: it depends on the site and surroundings. Every installation has different soiling factors at play, causing some to get dirtier much quicker than others. Even factors like prevailing winds can cause different sites to soil differently. This is why we always recommend that a system owner review their system’s production numbers to make the final determination on whether a cleaning is necessary. Most systems that are installed these days monitor output numbers through an app, or the system owner can typically contact the installer to check those numbers for them.

When reviewing the production of a system, we always recommend that a system owner looks over the span of at least 2+ years. System production can vary greatly from month to month and sometimes even from year to year, if there were production issues at any point during the year. Looking over the span of a couple years’ time will give an accurate view of how much production loss a system is experiencing. We also offer on-site solar washing inspections for solar owners in the greater Southeastern Pennsylvania area, where we can inspect your system and give an honest recommendation for whether cleaning is needed.

Where To Go from Here

If you are an owner of a solar system, whether residential or commercial, consider the environment that your system is in. Monitor the system’s output over an extensive period of

time, or look back over its output over the last number of years. From there, you can run some numbers to see how much your savings have decreased and make an informed decision of whether or not your system needs a cleaning to get back to maximum efficiency.

Want to maximize your solar savings? Contact us for safe, professional solar panel cleaning in Southeastern Pennsylvania.