Your solar panels may be quietly losing value without you even noticing.
An unmaintained solar panel system can experience an average annual efficiency loss of 2%–7%, while a well-maintained system can keep degradation below 1% per year. Over ten years, that difference can translate into more than 30% less energy produced.

In other words, proper maintenance has a direct impact on both your return on investment and the long-term safety of your system. In this article, we’ll walk you through how to maintain your solar panels properly—keeping them operating at peak efficiency while minimizing energy loss over time.

1. Why Solar Panels Need Maintenance

Many people assume that solar panels are a “set-it-and-forget-it” solution. This is a common misconception.

The power output of a solar panel depends on multiple factors, including sunlight intensity, temperature, and—most importantly—whether the panel surface is clean and unobstructed. While we can’t control the weather, we can make sure that panels are free from shading, dirt, and damage.

Dust, pollen, bird droppings, leaves, and other debris can accumulate on the surface and block sunlight. Beyond simple shading, this can lead to hot spot effects, where shaded cells stop generating power and instead act as electrical resistance, producing heat. Over time, this can cause permanent damage to the module and a significant drop in output.

In addition, as systems age, loosened mounting structures or electrical connections may become a safety risk during strong winds or heavy rain—potentially leading to structural failure, electric leakage, or even fire. In humid conditions, accumulated dirt can also create conductive paths, increasing the risk of short circuits.

Most photovoltaic systems are designed for a lifespan of 25 years or more. Regular inspection and cleaning help slow down component aging, ensure stable performance throughout the system’s life, and maximize your long-term return on investment.

2. When Should You Maintain Your Solar Panels?

Daily Monitoring via App

Today, most modern solar and energy storage systems offer real-time performance monitoring. For example, after connecting your system through the MARSTEK App, you can view real-time solar input power as well as historical generation data.

This makes it easy to see whether your solar panels are truly “doing their job.” If you notice a consistent and step-like drop in energy production under similar weather conditions, it’s often a sign that the panels are dirty or that another issue has developed.

Periodic Physical Inspections

In addition to app-based monitoring, we recommend inspecting and cleaning your solar panels once every quarter or at least twice a year.

After extreme weather events—such as sandstorms, heavy snowfall, hail, or strong typhoons—a mandatory safety inspection should be carried out. Check for cracked glass, loose mounting structures, and damaged cables to ensure the system remains safe and operational.

3. How to Clean Solar Panels Properly

Prioritize Safety

The best time to clean solar panels is early morning, late afternoon, on cloudy days, or at night. Avoid cleaning panels at noon when they are hot—spraying cold water on hot glass can cause thermal stress and cracking.

Before starting, make sure to switch off all circuits connected to the solar panels. Wear insulated gloves and non-slip footwear. If you’re working on a roof, always use a safety harness secured to a reliable anchor point, and never walk directly on wet or slippery panels.

Do not use high-pressure washers. Excessive water pressure can damage the glass, harm the cells, or cause water to seep into junction boxes.

Cleaning Tools and Methods

Ideal cleaning tools include a soft-bristle brush, a rubber squeegee, and a garden hose. For stubborn stains, a mild, neutral detergent (such as diluted dish soap) can be used.

Avoid hard brushes, abrasive cleaners, or strong acids and alkalis, as these can corrode the glass and frame.

Cleaning steps:

Ⅰ.Rinse the panel surface with clean water to loosen dirt.

Ⅱ.Gently scrub from top to bottom using a soft brush or sponge.

Ⅲ.Rinse again with clean water to remove residue.

Ⅳ.Use a squeegee to remove excess water and reduce water spots.

A Complete Inspection Checklist

After cleaning, perform a quick system “health check”:

• Inspect mounting structures for corrosion.

• Check whether bolts and clamps are loose.

• Look for deformation or damage to module frames.

• Examine the junction box on the back of the panel for proper sealing, bulging, or burn marks.

• Inspect DC cables for aging, cracks, or signs of rodent damage.

• Check for new sources of shading, such as growing tree branches, nearby construction, or stored objects.

4. Pay Attention to Inverter Operating Status

In most solar systems, panels are connected to an inverter before feeding electricity into the grid. The inverter converts DC power into usable AC power, making it a critical component of the system.

After cleaning your panels, take a moment to check the inverter as well. As the “brain” of the system, its health determines whether the energy collected by your panels is efficiently converted and utilized.

Ⅰ.Inspect cables connecting the inverter to the solar panels, battery, and grid. Look for loose connections, corrosion, burn marks, or abnormal heat buildup. Poor connections can cause energy losses and safety risks.

Ⅱ.Use the monitoring app (such as the MARSTEK App) to review not only total energy generation, but also real-time power, voltage, and current data. If the system consistently operates at low power on sunny days, or if efficiency drops suddenly, it may indicate an inverter fault or an issue elsewhere in the system—signaling the need for professional inspection.

5. Conclusion

Solar panels are not maintenance-free devices—they are long-term investments worth caring for.

A simple annual maintenance routine—combining safe cleaning, thorough inspection, and performance monitoring—can immediately improve energy output while ensuring reliable operation for decades to come. How you treat your system today will ultimately be reflected in your monthly electricity bills and your long-term peace of mind.

Now is a great time to give your “sunflowers” a health check. 🌻