Solar Panel Cleaning on Roof: A Beginner’s Guide

Going solar is a smart move for your budget and the planet. But just like anything installed outdoors, solar panels get dirty. A layer of dust or pollen can make them less effective. However, getting the most out of your solar panels is surprisingly simple. Just keep them clean. A layer of dirt acts like a shade, and you could be losing one-fifth of your potential energy without even realizing it. A gentle but thorough cleaning is all it takes to get them back to peak performance, ensuring your system—and your savings—are working at their absolute best.

In this beginner-friendly guide, you’ll learn why, how, and when to clean your solar panels — and when to hire a professional.

Why You Need to Clean Solar Panels?

Your solar panels work best when they are clean. A film of dust or pollen is like a tiny shade that reduces the efficiency of your system. The solution is easy: an occasional gentle wash or a streak-free window cleaner is all you need to get them back to peak performance and protect your investment.

Reasons to clean your panels:

• Dust and splatters from birds can create a shadow that stops sunlight from getting through.
• For maximum power generation, panels need a direct line of sight to the sun.
• Rain can help, but it leaves mineral stains on the panels behind that reduce the panels’ efficiency. 

Safety First: Before You Get on the Roof

In regions with varying roof designs and weather patterns, Maine Energy Experts advise homeowners to prioritize safety before any cleaning task. Therefore, before you clean your solar panels, always think about personal safety. Cleaning solar panels must be avoided if you lack knowledge about the cleaning process and safety rules. Consider hiring a pro if your panels are high or hard to reach. If you decide to clean them yourself, use a stable ladder, wear non-slip shoes, and make sure someone is around to assist you.

How to Clean Solar Panels on the Roof

Proper cleaning helps boost your solar panels’ performance. While cleaning them involves a simple process, protecting the surface is your top priority. This comprehensive guide will ensure you get it right—from preparation to the final drying.

1. Turn Off the Solar Panel System

Start by switching off your solar panel system. This ensures personal safety and prevents electrical damage. You can find the main disconnect switch near your inverter or breaker box.

2. Inspect the Panels from the Ground

First, just take a look from the ground. For light dust, a simple rinse is often all you need. However, for anything more serious, like pollen buildup, a deeper clean will be necessary.

3. Rinse with Clean Water

Use a garden hose with low pressure to rinse off dirt. Clean water helps loosen dust and bird droppings without damaging the glass. Here’s the important part: never use a pressure washer. Got hard or well water? For a final rinse, try using distilled water. 

4. Prepare a Gentle Cleaning Solution

A little dish soap in clean water works perfectly. It’s important to avoid strong cleaners or anything abrasive. They can permanently damage the panel’s protective surface. For an eco-friendly cleaning solution, mix one part white vinegar with eight parts water. 

5. Use a Soft Brush or Sponge

Dip a soft-bristle brush or sponge into your cleaning solution. Gently scrub the dirty panels to clean them. Do not use metal tools or hard brushes. If you’re cleaning from the ground, use an extendable brush designed for solar panels. Many solar panel cleaning brushes come with water-fed poles for easy rinsing.

6. Rinse Again Thoroughly

Make sure to thoroughly rinse the soap off when you’ve finished cleaning. Leftover soap film attracts dirt quickly. A final rinse with distilled water will preserve your panels streak-free and crystal clear if your tap water leaves stains.

7. Dry the Panels (Optional)

After cleaning the panels, you can let them air dry. Or you can use a soft microfiber cloth or squeegee. Avoid rough towels or paper wipes. They may leave scratches or lint. When the panels are completely dry, switch the system back on.

8. Check Energy Production

Once cleaning is done, monitor your solar power system’s output. You should notice an improvement in solar energy production. If not, consider checking with your installer — there may be another issue affecting performance.

9. Bonus Tip: Prevent Future Buildup

If you live in a dusty area, apply a protective coating recommended by your solar installer. This coating helps repel dust and water, reducing the need for extensive solar panel maintenance. 

You can also trim nearby trees or remove overhanging branches to minimize debris buildup.

When Should You Clean Your Panels?

You should clean your dirty solar panels on the roof once or twice a year. However, solar panels that are installed in an area with dense trees, dusty roads, or bird nests demand frequent cleaning. 

Early morning or late evening is the best time. The panels are cooler, and the soft light makes cleaning easier. Cleaning during midday heat can cause cracks or hard water spots.

How Often Should You Hire a Professional?

Even if you prefer DIY cleaning, it’s smart to schedule professional solar panel cleaning at least once a year. Professionals use deionized water systems, telescopic brushes, and gentle cleaning methods that reach tough spots safely.

Professional solar panel cleaning typically costs around $10 to $20 per panel, depending on size and location. For homeowners with solar panels on steep or multi-story roofs, this is a safer and more thorough option.

It’s also good for maintaining the system’s warranty, as many manufacturers recommend using certified cleaners.

Final Thoughts

Cleaning your solar PV panels on your roof is not just about looks — it’s about the efficiency of your solar system and its longevity. Regular cleaning and maintenance protect your investment and ensure your solar cells perform at their best. You can clean the panels yourself using clean water to remove dust, a soft-bristle brush, and mild soapy water, or hire a cleaning company or professional cleaning service. Occasional cleaning is usually enough, but if your panels are covered in dirt or debris, consider cleaning more often.