Why Do Solar Panels Need Cleaning?

Solar panels are a smart investment—but like any investment, they require care to perform at their best. Over time, panels accumulate layers of dust, pollen, bird droppings, and air pollution. This grime can significantly reduce solar efficiency. According to a study by the National Renewable Energy Laboratory (NREL), panels in particularly dusty environments can lose as much as 25% of their energy output if not cleaned regularly. Typically in the Davis and Weber county area we see dust and debris block solar arrays. This build up reduces their power output by closer to 16%. But as you can imagine, this varies greatly and is more of an average that we’ve personally seen.

Before Cleaning

After Cleaning

Why Does Rain Not Clean Solar?

It’s a common misconception that rain will keep your solar panels clean. While it may rinse away loose dust, rain often leaves behind mineral deposits and water spots. Especially in areas with hard water. Think about your car windshield, does it stay spotless after a rainstorm? The same principle applies to solar panels. Rain can actually contribute to buildup over time, particularly at the bottom edge of the panels where water collects and evaporates. Somtimes this blocks entire rows of cell’s which could hault a panels entire production depending on your solar cell technology. Smog and other deposits also build up overtime. All of these factors contribute to significant buildup overtime.

Why Is Solar Panel Cleaning Important?

Keeping your panels clean isn’t just about appearance—it’s about performance. Even light layers of dirt can scatter sunlight, lowering the amount of energy your system can produce. In commercial or high-output residential systems, this can translate to noticeable losses on your power bill. Regular cleaning ensures your panels are operating efficiently year-round, preserving the return on your solar investment. Some solar companies require that your panels be cleaned regularly to maintain warrenties.

How Often Does a Solar Panel Need to Be Cleaned?

This varies depending on your environment. If you live near farmland, construction, or areas with low rainfall (like Northern Utah), experts recommend cleaning 1 to 3 times a year. Homes closer to urban pollution or desert regions may need more frequent service. Solar manufacturers often suggest biannual cleaning to stay in compliance with warranty requirements.

Many homeowners consider doing it themselves, Which at first might seem like an economical option. but DIY cleaning comes with its own set of challenges. First, the upfront cost: a proper setup requires deionized (DI) water to avoid spotting and leaving streaks or mineral deposits. you also need specialized brushes that wont scratch panel coatings, telescoping poles, and safety gear. Without DI water, cleaning with tap water can cause mineral deposits that harm your panels in the long run.

Then there's the issue of safety. Most panels are mounted on rooftops, and without proper training or equipment, climbing up there poses real fall risks. Even minor slips can result in serious injuries—or damage to the panels themselves.

That’s why many solar owners opt for professional cleaning. It’s not just about the quality of the clean—it’s about peace of mind. Having your system maintained by trained technicians who use the right equipment and methods ensures your panels are protected, your warranty stays valid, and your energy savings stay high.