How to clean solar panels on roof successfully

Switching to a solar system is a great way to reduce your carbon footprint and lower your energy bills. That said, to keep your investment running efficiently, regular maintenance is a must. One often-overlooked task is solar panel cleaning. If you’re wondering how to clean solar panels on roof, this blog is for you. 

Whether you’re dealing with bird droppings, dust buildup, or pollen, learning how to clean solar panels on the roof can significantly improve your energy output. So let’s walk you through the process of cleaning your panels, the tools you’ll need, what mistakes to avoid, and when it’s time to call in a professional cleaning service.

Why should you clean your solar panels?

Solar panels need direct sunlight to generate power. Over time, grime, leaves, bird droppings, and pollution can block sunlight from reaching the photovoltaic cells. A dirty panel won’t necessarily stop working, but its efficiency can drop, sometimes by 15% to 25%, depending on how dirty it is.

Studies from the National Renewable Energy Laboratory (NREL) show that regular cleaning can improve performance on average by up to 12%.

If your solar system isn’t producing the energy you expect, it might be time to clean the panels.

What are the signs that your solar panels need cleaning? 

You don’t need to clean your panels every week, but there are signs that indicate it’s time for a cleaning session:

• Visible dirt or grime: If you can see dust, leaves, or bird droppings, it’s affecting efficiency.
• Lower energy output: If your solar system isn’t generating as much power as usual. Many homeowners monitor energy output via their solar system’s app. A noticeable drop in performance can signal that it’s time to clean the panels.

When is the best time to clean panels?

Knowing the right time to clean your solar panels can make all the difference. The ideal cleaning time should be:

• Early morning or late evening, when solar panels are cooler and easier to clean.
• Spring and fall are great seasons for cleaning because there is less pollen than summer, and less grime than after winter rains.
• After a storm or a long dry spell. It’s a good idea to inspect the panels for accumulated dirt or debris.

Remember, rain can help rinse your panels, but it doesn’t fully replace manual cleaning. Especially if you have a lot of bird poop or sticky residue.

How often should you clean your panels?

Generally, cleaning your panels twice a year is sufficient, but if you live in a dusty area or near trees, you may need to do it more often. For example, if you live near:

• Construction sites
• Farms
• Highways
• Or places with frequent bird activity

How to clean solar panels safely: The steps

Cleaning and maintaining home solar systems isn’t complicated, but doing it wrong can cause a lot of damage. Here’s the best way to clean panels without risking scratches or other issues.

Turn off the system 

For safety, some experts recommend turning off your solar system before cleaning. Keep in mind that while some systems are designed to handle water exposure when running, others are not. It’s best to check your manufacturer’s guidelines for confirmation. 

Use the right tools

Avoid harsh chemicals, abrasive materials, or pressure washers, as these can scratch or damage the glass. Instead, use:

• A soft brush or sponge (non-abrasive)
• A garden hose with a gentle spray nozzle
• Mild soap (such as dish soap) mixed with water
• A squeegee for streak-free drying

Clean early or late in the day

Never clean solar panels in direct sunlight. The heat can cause water to evaporate quickly, leaving streaks and residue. Early morning or late afternoon is the best time to clean.

Spray and gently scrub

Start by rinsing the panels with water. This will help loosen the dirt. Then, use a soft brush or sponge with soapy water to gently remove stubborn grime such as bird droppings. Avoid scrubbing too hard, as scratches can damage your panels (can be a costly mistake!) and reduce efficiency.

Rinse and dry

After cleaning, rinse thoroughly with clean water. If possible, use a squeegee to prevent water spots.

Read more: The best solar financing options

What are the most common mistakes to avoid when cleaning your solar panels?

• Using harsh chemicals. Remember, bleach, ammonia, or strong detergents can damage the anti-reflective coating on panels. Stick to mild soap and water.
• Using pressure washers. High-pressure water can crack the glass or damage seals. A garden hose with moderate pressure is safer.
• Walking on panels. Keep in mind that the solar panels aren’t designed to support weight. If you need to access hard-to-reach areas, use a long-handled brush or hire a professional.
• Ignoring safety. If your roof is steep or high, consider hiring a cleaning service instead of risking a fall.

When should you hire a professional cleaning service?

While DIY cleaning works for many homeowners, there are times when hiring a pro is the best choice. Especially if you have:

• Hard-to-reach panels: If your roof is steep, high, or too dangerous for DIY access.
• Stubborn stains: Bird droppings, sticky residue, or tree sap may require special treatment.
• Warranty concerns: Some manufacturers require professional cleaning to maintain warranty coverage.

If you decide to hire a professional, look for a solar panel cleaning service with good reviews and proper insurance. Expert cleaning services have the right tools, safety equipment, and experience to do the job without causing damage.

Hiring a professional solar panel cleaning service usually costs between $100 to $300, depending on the size of your system and location.

What are some useful tips to reduce future build-up?

Want to cut down on cleaning frequency? Here are a few preventative tips:

• Install bird deterrents such as spikes or mesh around the panels to prevent droppings.
• Trim nearby trees that shed leaves or sap.
• Use panel coatings (if recommended by the manufacturer) that reduce dust adhesion.
• Schedule annual inspections to detect dirt, corrosion, or shading issues early.

How to clean solar panels on roof: Bottom line

Keeping your solar panels clean ensures they operate at maximum efficiency, saving you money and energy. By using the right tools, avoiding harsh chemicals, and cleaning at the right time, you can maintain your solar system without unnecessary risks.

If cleaning your panels seems too difficult or dangerous, don’t hesitate to hire a professional. A small investment in home maintenance can lead to big savings in the long run.

Written by Ramona Sinha. June 11, 2025

Ramona is the Senior Content Writer for Kukun. This experienced blogger uses simple and succinct words to decipher the complex phenomenon called life. She has written articles covering a broad range of topics, such as real estate, lending and mortgage, finance, business, taxation, home designs, home improvement projects, decor concepts, and more. An avid traveler, she’s a digital nomad at heart and an animal lover from the depth of her soul.