5 Mistakes to Avoid When Cleaning Solar Panels During Heatwave

Solar panels are one of the smartest investments a homeowner can make. They save money, reduce your carbon footprint, and provide long-term energy independence. But like any other piece of equipment, they need a little care to perform at their best.

One key part of maintenance is solar panel cleaning. Over time, dust, bird droppings, pollen, and pollution build up on the glass surface of panels. This layer reduces the amount of sunlight reaching the cells, lowering energy output. In fact, dirty panels can lose up to 20% efficiency if not cleaned regularly.

But here’s the catch: cleaning your solar panels the wrong way—especially during a heatwave—can do more harm than good. Let’s go over the five most common mistakes people make, and the best way to clean solar panels safely.

1. Cleaning Panels in the Middle of the Day

Many homeowners assume a sunny afternoon is the perfect time to wash their panels. In reality, this is the worst moment to do it. During a heatwave, panels can get extremely hot—often 140°F (60°C) or higher. Spraying cold water on such hot glass can cause sudden temperature shock, leading to cracks or permanent damage.

Tip: Schedule cleaning early in the morning or later in the evening when panels are cooler. This keeps the glass safe and ensures water doesn’t evaporate instantly.

2. Using Harsh Detergents or Pressure Washers

It might be tempting to grab strong soap or a pressure washer to get panels sparkling clean. Unfortunately, this approach can scratch the glass or strip away the protective coating. Damaged surfaces reduce efficiency and may void your manufacturer’s warranty.

Best way to clean solar panels: Use soft water (or distilled water), a gentle biodegradable soap if needed, and a microfiber cloth or soft brush. This keeps panels clean without harming them.

3. Ignoring Safety Precautions

Heatwaves already make outdoor work exhausting. Climbing onto a roof with a bucket of water can become dangerous quickly. Many accidents happen because homeowners underestimate how slippery wet solar panels can get.

Tip: Always prioritize safety. If your panels are hard to reach, consider hiring a professional service that specializes in solar panel cleaning. Professionals have the right equipment and know-how to clean panels safely, even in extreme weather conditions.

4. Forgetting About Water Quality

Not all water is created equal. In many regions, tap water contains minerals that leave behind streaks or white spots when dried under the sun. Over time, this residue can form a cloudy layer that reduces panel efficiency.

Tip: When cleaning solar PV panels, try using deionized or distilled water. This ensures a spotless finish without mineral buildup.

5. Cleaning Too Often—or Not Often Enough

Some homeowners clean panels every week, while others ignore them for years. Both approaches are mistakes. Over-cleaning can scratch surfaces, while neglect leads to energy loss.

Best practice: Inspect panels every few months. In areas with frequent dust storms, wildfires, or heavy bird activity, cleaning may be needed more often. Otherwise, once or twice a year is usually enough.

Bonus: The Smart Alternative

If the thought of scrubbing panels under the summer sun doesn’t appeal to you, consider automated or professional solutions. Some companies now offer waterless cleaning systems or robotic brushes designed specifically for solar panel cleaning. These tools save time, conserve water, and keep your system running at peak performance.

Wrapping It Up

Keeping your panels clean is essential for getting the most out of your solar investment. But during a heatwave, rushing into it without the right approach can damage panels, reduce efficiency, and even put your safety at risk.

By avoiding these five mistakes—cleaning at midday, using harsh tools, ignoring safety, overlooking water quality, and improper cleaning schedules—you’ll protect your panels and maintain maximum output.

Remember, the best way to clean solar panels is with gentle care, proper timing, and safe techniques. And if in doubt, calling in a professional is often the smartest option. With the right approach to cleaning solar PV panels, you’ll enjoy cleaner energy, lower bills, and a system that lasts for decades.