Cleaning Solar Panels: Why, When, and How You Should Do It

A car that’s well-oiled and serviced performs better and for longer. Just as we want our set of wheels free of mud, we like our windows crystal-clear as well. The same way that way we approach solar panels should be no different. By keeping our solar panels at their best, we can expect that they will perform at their optimum, remain free of any safety hazards, and ensure that they continue to provide energy to our home or business for years to come.

This article tackles the most significant questions surrounding solar panel maintenance. We will discuss the main sources of dirt buildup, the correct ways of cleaning your solar panel, and situations requiring solar panel cleaners or professional maintenance.

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Common solar blockers – dust, leaves, and water

Regular cleaning of solar panels is crucial to maintain their optimal performance. Several factors influence the frequency of cleaning, including location, weather conditions, and surrounding pollutants.  

While heavy rainfall may occasionally clear away dust and debris, studies indicate that dust accumulation can swiftly reduce efficiency by 5% or less. Properly maintained panels can generate 3.5% more energy, while uncleaned panels may lose up to 30% of their efficiency.  

Dust isn’t the only culprit; leaves can also hinder sunlight, affecting panel performance. Solar systems in dust-prone areas, such as near roads or farms, demand more frequent cleaning. 

Neglecting to clean panels in these areas can significantly impact energy production. Research suggests that dust can reduce efficiency by up to 40% in such environments.

Bird droppings: The main culprit

Bird droppings can affect a panel’s performance to a greater degree than dust buildup. The common string-inverter PV solar system might result in minimal or no energy being produced if bird droppings cover part or all of just one solar panel. A micro-inverter solar system might see the affected panel/s producing no or limited power. You can read more about string and micro-inverters here.

Trees situated near your panels will not only drop their leaves and branches but attract birds as well. These cause bird droppings and debris over time, which will not only require cleaning and clearing but pose a safety hazard. Hence, a monthly or annual gutter cleaning, and bird proofing, may be necessary. 

Another consideration for keeping your panels performing at their best is the angle. Flat arrays will need more servicing as water can pool up there, leaving muddy residue as soon as it evaporates. On the other hand, proper-angled arrays can take advantage of rain without having muddy residue. This is because rain can effortlessly slide across them, keeping them mostly free of dust buildup and pollutants.

Why professional solar panel cleaning is the most ideal option

Australia has more than 3.6 million solar power systems installed across rooftops as of September 2023. Australia’s clean energy transition continued in 2022, with renewables reaching 35.9% of total electricity generation, a steady increase from 2021, as the Clean Energy Council reported. This marks a significant climb since 2017 when renewables only comprised 16.9% of the mix.

Remember to follow safety guidelines when using this approach to ensure safe solar and gutter cleaning. Read this article here to learn more about how to clean solar panels efficiently and safely.

As much as many homeowners want to keep a tight budget and prefer a DIY approach, solar panel cleaning services provide a professional service whilst following the industry’s safety protocols. Cleaning panels isn’t as straightforward as it seems. 

When is the best time to ask for help from solar panel cleaning experts?

A bit of dust buildup may not be much of a problem and may be able to be tackled with your garden hose. If your solar panels are heavily soiled or you are uncomfortable cleaning them yourself, it is best to ask for help from a professional solar panel cleaner.

Cleaning professionals or solar panel cleaners can handle difficult problems and ensure that you are free from any risk associated with getting on your roof. Coordinating with experts can guarantee you the best cleaning standards. 

How to clean solar panels at home?

Most DIYers use the materials they have at home. If you prefer a DIY cleaning, the best way to clean solar panels, we suggest you opt for clean water, detergent, and a good quality soft brush when applying soapy water. Only use a mild detergent if some parts of the panels need some extra cleaning. Wipe dirty areas with mild detergent and a soft cloth-covered sponge safely and thoroughly. This prevents strong chemicals from marking your clean solar panels. Be sure to follow safety precautions when cleaning solar panels on your roof.

Here are some additional tips for cleaning your solar panels:

• Avoid cleaning solar panels on hot, sunny days. This can cause the water to evaporate quickly and leave streaks.
• Don’t use a pressure washer. The high pressure can damage the panels.
• Use a soft brush or cloth. A hard brush can scratch the panels.
• Rinse the panels thoroughly with clean water. This will remove any soap residue.
• Clean your solar panels regularly. This will help keep them free of dirt and debris and ensure that they operate at their peak efficiency.

Locations that may require more frequent solar panel cleaning

• Coastal areas: Coastal areas are prone to the buildup of marine layer residue, which can leave an obstructive film on solar panels. This residue can be difficult to remove, significantly reducing solar panel efficiency.
• Cities and towns: Cities and towns are often exposed to airborne pollutants such as dust, dirt, and soot. These pollutants can also accumulate on solar panels and reduce their efficiency.
• Areas near highways or construction sites: These areas are exposed to high levels of airborne debris, such as dust and dirt from vehicles and machinery. This debris can quickly accumulate on solar panels and reduce their performance.
• Areas with frequent dust storms: Dust storms can deposit a thick layer of dust on solar panels, significantly reducing their efficiency.
• Areas with low rainfall: Areas with low rainfall are less likely to be naturally cleaned by rain. This means that solar panels in these areas may require more frequent cleaning to maintain efficiency.

Solar power equipment and maintenance

You can always get the job done using solar panel equipment tools such as an extentool, rotary solar brushes, and a water hose. You can use these tools while staying on the same ground level. However, in some cases, going up to the roof is necessary to get the job done. We also recommend using a specific solar panel cleaning solution to get the best results.

Needless to say, safety precaution is a must when undertaking this difficult cleaning task. Always use safety equipment such as a safety harness to prevent you from falling to the ground – a method used by professional cleaning experts. Don’t forget to wear a hard hat when doing this task. Always keep these tips in mind when cleaning solar panels yourself.

Ideas for keeping efficient solar panels

While DIY ideas and professional services help keep your panels clean and maintained, the solar industry also consistently delivers new ideas for much more seamless upkeep. These ideas include: 

• Special coatings for dust repellant and soil reduction. 
• Robotic cleaners for dirt removal. They use soft brushes and air blowers. 
• Kipp & Zonen’s commercial tool for dirt measurement.

Kipp & Zonen’s DustIQ monitor system uses LED and a photodiode to monitor dirt buildup on the solar production array. This tool helps solar farm operators to identify the ideal time to clean their arrays for optimum performance.

Industry experts suggest cleaning your panels at least twice a year. Doing so keeps your investment in its best shape and performing as expected.

Failing to give your panels the maintenance they deserve may also mean losing energy. Remember that losing energy means losing money. 

Does cleaning solar panels make a difference? Yes, indeed. Below are energy production percentages you may lose per quarter if you fail to give your panels the required maintenance.

• Year 1 Q1: 5% Energy Loss
• Year 1 Q2: 10% Energy Loss
• Year 1 Q3: 15% Energy Loss
• Year 1 Q4: 20% Energy Loss
• Year 2 Q1: 25% Energy Loss
• Year 2 Q2: 30% Energy Loss
• Year 2 Q3: 35% Energy Loss
• Year 2 Q4: 35% Energy Loss

Safety tips for DIYers solar panel cleaning

Rain can often help clean general dust away from dirty solar panels, and in this case, professional solar panel cleaners may not be necessary. However, living in a high-pollutant area may bring extra dirt and debris that will necessitate a professional solar panel cleaner or a garden hose to clean your panels effectively.

If too much dirty water or stubborn grime on the array will require you to go up on your roof, always follow safety precautions. Use appropriate safety equipment, including wearing a safety harness and hard hat when cleaning regularly.

Solar panel cleaning will require a clean sponge and mild detergent to remove grime effectively. If cleaning your solar panels yourself will require heavy upkeep, leaving the task to the professionals can never go wrong.

Frequently Asked Questions (FAQs)

What is the best way to clean solar panels?

A mild soap and water solution is the best way to clean solar panels. You can use a soft sponge or cloth to apply the solution to the panels and then rinse them with clean water. Avoid harsh chemicals or abrasive materials, as these can damage the panels.

If you live in an area with hard water, use distilled water to rinse your panels. Hard water can leave mineral deposits on the panels, reducing their efficiency.

You should also avoid cleaning your panels on a hot day. The heat can cause the soap to dry too quickly, leaving streaks on the panels. It is best to clean your panels on a cool, cloudy day.

Do you have to turn off solar panels to clean?

Yes, turning off solar panels before cleaning them is essential to ensure safety and prevent electrical hazards. When exposed to sunlight, solar panels generate electricity, and even a small amount of residual current can pose a risk of electrocution. Turning off the system eliminates this potential danger, allowing for a safer cleaning process. 

Is it OK to hose off solar panels?

Yes, it is generally safe to hose off solar panels to remove dirt and debris. It is recommended to do so regularly to ensure that your panels are operating at peak efficiency. Rainwater will naturally clean your panels to some extent, but it is not always enough to remove all of the buildup. Hosing your panels down will help to remove any remaining dirt, dust, pollen, or other contaminants.

Is it OK to use Windex on solar panels?

The safety of using Windex on solar panels remains debated among experts. Consulting with your solar panel installer or manufacturer is always recommended to determine the most suitable cleaning method for your specific panels. While Windex is generally considered safe for cleaning windows, it’s essential to exercise caution when using it on solar panels. Dilute Windex with water, avoid using it on hot or sun-exposed panels and refrain from using ammonia-based Windex as it can damage the anti-reflective coating on certain solar panels.

Updated December 2023.

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