Make Your Solar Panels Shine: Here's a Step-by-Step Cleaning Guide

By Grant Desselle

August 15, 2024

Solar panels allow you to save money on utilities and keep the lights on during power outages. But if enough dirt and grime accumulate, it's only a matter of time before you go crawling back to Big Electricity and rejoin the grid-reliant masses.

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Do Solar Panels Need to Be Washed?

Solar panels naturally absorb less light on cloudy days, but layers of dirt, dust and debris can have a similar impact on their efficiency.

How Do You Know It's Time to Clean Your Solar Panels?

Assuming there's no large "Wash me!" message, reduced power output indicates your solar panels may need to be cleaned. Dirty solar panels aren't the only cause of reduced efficiency, so you'll want to complete a visual inspection to confirm that's the reason. If you haven't noticed a drop in the performance of your solar system but find leaves, bird poo or other debris, it's a good idea to clean them anyway.

How Do You Clean Solar Panels?

Cleaning photovoltaic panels can be accomplished in just a few hours. Though handy, you won't need any special solar panel cleaning equipment — just a few common household items.

Cleaning solar panels is similar to cleaning a car. With the system turned off, remove dirt and debris with water and then wash the panels with a cleaning solution. Then, rinse off the remaining solution and residue and allow the panels to dry. Repeat the process as necessary.

Things You'll Need

Garden hose
Mild cleaning solution or dish soap
Soft brush or squeegee
Lint-free towel
Extension pole
Safety gear such as harness and boots

Safety First

Turn off your solar panel system, and read the manufacturer's documentation. It often lists recommendations for solar panel maintenance, including whether the panels need to be frequently cleaned, if a special solar panel cleaning solution is required and whether specialized tools such as a solar panel cleaning brush are suggested.

If your solar panels are mounted on a roof or in another elevated location, we recommend using a safety harness in addition to footwear appropriate for working on roof surfaces. (Or, if you're not confident in your abilities, please just call a professional.)

Gather Tools and Materials

Get your garden hose and mix your cleaning solution with clean water. If you can't find solar panel cleaner, a mild cleanser such as dish soap works well.

If you have roof-mounted solar panels but feel more comfortable working on the ground, attach your brush or squeegee to an extension pole. A short pole can also help reduce the amount of bending over you'll need to do and prevent unnecessary back strain.

Clean the Panels

First, rinse the panels with the hose to remove as much dirt and debris as possible. Be careful if you decide to use a pressure washer, as the higher-pressure nozzles could damage the panels.

Using a soft brush or squeegee, clean the panel surfaces with the solution you mixed earlier. Pay attention to the corners where dirt is often harder to remove.

Rinse off the panels again, removing any remaining dirt and cleaning solution, and allow the panels to dry. If you can't wait for them to air dry, use a lint-free towel and dry the panels gently.

Inspect the Panels

Check the panels for stains and ensure all the dirt and debris have been removed. If necessary, clean the panels again.

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How Often Should You Clean Solar Panels?

Several studies have examined how the accumulation of dust translates into lost revenue for industrial solar farms. For consumer installations, most solar providers recommend cleaning PV panels at least twice a year, depending on the environment.

People living in dry environments may notice that their panels collect a lot of dust that sticks around because of their limited rainfall. But if you have many nearby trees and frequent wind, your panels may become dirty frequently as well.

While searching for the point of diminishing returns, one study concluded that solar panels need more frequent cleanings during different times of the year to maximize profit. If you're mathematically inclined, you can use a formula to determine how frequently your solar panels need to be cleaned to receive the most financial benefit.

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