Does Cleaning Solar Panels Make a Difference?

Solar panel cleaning can maintain their ability to absorb sunlight. These panels are usually installed at a steep angle, so they get self-cleaned when there is a downpour. Dust and debris can affect solar panel efficiency to some extent, but is it worth opting for a cleaning service or cleaning them yourself? Let’s find out.

Does Cleaning Solar Panels Make a Difference?

Yes, it does make a difference by improving their performance. Dirty solar panels reduce the overall output of the system. In general, the percentage of electricity lost on dirty panels varies with them losing between 5% and 35% on average, but this changes from one factor to another.

Frequent cleaning and proper maintenance practices ensure the highest efficiency for the maximum power generation by solar panels. Occasionally dust, leaves or bird droppings tend to be cleaned by natural elements such as wind and rain. But if there is too much accumulation of such substances on panels they may not work efficiently.

Is Rain Enough to Clean Solar Panels?

Yes, for light dust and dirt accumulation, rain is enough to clean your panels. Mounted and oriented panels easily get washed by rain, removing all dust and debris. But panels on a flat roof are not effectively cleaned by the rain. Also, tougher stains require manual intervention, even if you have mounted panels.

Read in detail about 11 Major Factors Affecting Solar Panel Efficiency

Can you Pressure Wash Solar Panels?

No, it is not recommended to pressure wash your solar panels. They are designed to withstand extreme weather conditions and heavy rainstorms, but that does not count in pressure washers. High water pressure can damage the photovoltaic cell.

However, if for cleaning large installations you are preferring a pressure washer, make sure to keep the setting low and use a wide nozzle.

Can Water Destroy Solar Panels?

No, most of them are rated IP67. A mere splash or even shower of water cannot harm it but if one uses high-pressure washers this can potentially bar the surface or damage PV cells.

Is it Okay to Hose Off Solar Panels?

Yes, a gentle stream is enough to rinse or shower the solar panels.

What Are the Reasons for Dirty Solar Panels?

Here are some of the factors that cause panels to get dirty

• Bird Droppings: Bird droppings can build up over time, especially if the panels are installed on a flat surface reducing output. Rain often can’t clean them completely.
• Dirt on Frame: Dirt accumulates around panel edges, causing losses and potential hotspots.
• Debris: Leaves and twigs from nearby trees can get stuck between panels, creating shade.
• Bacterial growth: Fungi, lichen, or mold can develop on panels due to humidity and dampness, similar to roofs.
• Industrial Pollution: In some areas, factory exhaust or dust can stick to panels, being hard to remove.

Bonus fact: Cicada rain is common in areas with native trees. This happens when cicadas excrete tree sap that gets mixed with pollen and dust to create hard-to-remove residues on solar panels.

Do Solar Panels Work Better if They are Clean?

Yes, they will work better if they are clean but the difference is very minimal. The University of California found that during a very dry season, they only lost around 7.4% of performance. Another study in Arizona found only a 1% improvement in performance from regular cleaning.

It is recommended that the panels should be cleaned every 2 or 3 years but this interval can change as other factors such as location, weather and environment will come into play as well.

Find out other 8 Benefits of Cleaning Solar Panels

How Much Does It Cost to Clean Solar Panels?

Solar panel cleaning can cost around $10 to $20 per panel or $150 to $500 total on average, with most homeowners spending about $325. However, one thing to keep in mind this cost can change depending on factors like 

• Panel size, number, and type
• Panel condition
• Roof height and steepness 
• Difficulty 
• Climate 
• Materials and equipment used
• Contracts and Warranties 
• Commercial or residential 

Here is an estimate of the cost per number of panels.

Panel numbers	The average cost to clean
5 to 15	$50 to $300
15 to 25	$100 to $500
25 to 35	$250 to $700
More than 45	$900+

Cross-Reference: Costs of solar panel cleaning

What is the Best Way to Clean Solar Panels?

It’s always safe to have experts clean your solar panels for you unless they are easy to access. Even so,

• They make sure that company compliances concerning insurance are addressed and they also guard your investments.
• They can help to flag any issues before they graduate to major problems that will be expensive to solve.
• Their staff is properly trained and has the correct safety gear on them.

What to Avoid While Self-Cleaning Solar Panels?

If planning to do a DIY cleaning, here are a few tips.

• Never use pressure washers, severe chemicals, and rough cleaning pads. They can scratch the panels’ surfaces which will reduce performance in the same way as dirt and debris.
• Do not go up to the roof. It is dangerous when water and soap get mixed because it can make the roof slippery which may lead to physical and electrical accidents.
• Hiring a professional is a good idea if you are having trouble cleaning them off. It will save your life and warranty too.

How to Clean Solar Panels Yourself?

On the other hand, if you have easy access to the panels or if they are installed on the ground. You can follow these steps to clean them yourself.

Step 1: Ensure that you turn off your solar system at the switchboard for security reasons.

Step 2: Rinse panels thoroughly from a safe place to get rid of loose dirt.

Step 3: Make a mild solution of soap or use a cleaner specifically designed for panels. Stay away from harsh detergents.

Step 4: Pour some solution with a smooth cloth or squeegee. In case of stubbornness, gently rub with soft brushes.

Step 5: Spray panels to remove all cleaning agents, especially around the edges.

Step 6: Wipe using a clean, soft cloth to avoid water spots.

Step 7: Finally check out if there are any missed spots and soapy materials left behind. Do the cleaning in case need be.

So, is cleaning solar panels worth it? The answer depends on your situation. If you live near farms or factories, in an area with scarce rainfall, or have flat-mounted panels, regular cleaning can be beneficial. However, for most people, nature does an adequate job. Rain and wind typically keep panels clean enough, and the performance boost from manual cleaning is often marginal.

Recommended: Solar Panel Removal and Reinstall Process