Solar Panels Can Be Cleaned by The Rain, But Is It Enough?

by | January 15 , 2023 | Solar Panel Cleaning, Window Cleaning Tips | 0 comments

solar panels cleaned by rain

Rain can be a great way to passively clean solar panels.

Can you postpone solar panel cleaning if rain is forecasted?

Rain may clean most dust buildup, but it could do more harm than good. In arid climates found in La Quinta, Palm Springs and Palm Desert, rain is rare. We only get about eleven rainy days on average. Do these brief spurts provide enough cleaning power?
dirty solar panels in La Quinta, California

Rain isn’t always enough to clean solar panels. Take this panel for instance after a brief shower.

Does rain help remove build up? How much rain is needed?

In a study conducted at Stanford University, researchers measured a significant performance reduction after a year’s worth of dust buildup. Another study found that extended periods without rain, daily energy losses can be as high as twenty five percent. In dry climates like Rancho Mirage and Indian Wells, dust buildup is a major issue. The problem remains simple: a lack of rain results in dust buildup getting progressively worse. Regular rainfall can rinse away dirt and keep solar panels producing at optimal capacity.
One could assume solar panels in areas with frequent rainfall would require less maintenance. This may be mostly true but not entirely. Other factors such as pollen, bird droppings and leaves can soil panels. These deposits can create a layer which may not wash away from rain. Ponder this, if rain was really an effective method of cleaning, why is the car wash so busy when a rainstorm ends? With airborne pollutants, rain might not clean anything. If wind is added to the mix, your PV cells may become dirtier.
solar panels with pigeon nesting problem

The type of soiling on solar panels can determine the best course of action

Solar Panels And Environmental Factors

Certain environmental factors including rain can contribute to dirty panels. For instance, areas that receive heavy rainfall also tend to have algae growth. Algae and mildew can create a layer that obscures UV rays. Your production can be greatly reduced over time. We’ve seen this case quite a few times when performing solar panel cleaning in Redlands, California. Landscaping can also affect PV performance. Country Clubs in Palm Desert and La Quinta use powerful sprinklers for their golf courses. The mist carried by wind can develop hard water stains on solar panels. These are examples of water not always being the answer.

How Do You Know When It’s Time For Solar Panel Cleaning?

If you’ve had solar panels for at least a year, you’ve probably noticed a pattern in production.  You might’ve noticed reduced output in the winter and spring. The main reason is that the sun travels further away from The Coachella Valley in the winter. We also have shorter days in the winter. Spring, on the other hand arrives with abundant sunshine. The season change does bring pollen, falling leaves and birds as well. This is why ShinePro Window Cleaning recommends solar panel cleaning at least twice a year. The best test to see if you’re ready for service is monitoring production.

solar panel cleaning in Beaumont, California

The best method for solar panel cleaning is scrubbing and washing with deionized water.

Tips on Cleaning Solar Panels

Cleaning your solar panels shouldn’t cost an excessive amount, nor should it be an overly complicated process. In a pinch, spraying them off from the ground with a garden hose may help. But the thicker the buildup, the more likely you will need to hire a professional or purchase specialized cleaning systems. If you can’t afford a Pure Water Deionization System, try this:

  1. Fill your bucket with a 3% soap-and-water solution. 
  2. Rinse solar panels with clean water to clear away loose dirt. 
  3. Use soft scrubber and soapy water from the bucket—or mixing sprayer—to gently wash the surface of the panels. 
  4. Rinse solar panels with clean water from the hose a second time. 
  5. Squeegee panels dry. 
  6. Follow the same process, changing your position as needed, until all panels are clean.

When In Doubt, Call A Professional Solar Panel Cleaner

Some things to consider before trying to clean your own panels include: safety, convenience and costs. Take these bullet points for example:
  • Your roof is too high, steep or slippery to walk on. 
  • You do not have a ladder tall enough or proper cleaning tools. Buying and storing cleaning tools and equipment only use once a year makes little sense. 
  • You have physical disabilities, making climbing ladders and walking on rooftops dangerous. 

For most solar customers, professional cleaning is the best option. So how do you choose your solar panel cleaning provider? Check out their online reviews on sites such as Yelp and Google.

Final Thoughts…

Solar panels need regular cleaning. Rain can be a great supplement to professional cleaning though, not entirely. Palm Desert, La Quinta and Palm Springs often experience high winds. These areas receive very little rain thus do not get rinsed enough. It is better to err on the side of caution and call a professional. ShinePro Window Cleaning serves customers from Indio all the way to Redlands, California. Call us today to book your service or for any question related to solar panel cleaning, pressure washing and window cleaning!

Brandon Scott COO of ShinePro Window Cleaning

 

 

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