Is Solar Panel Cleaning Worth It?

In most parts of the US, solar panel cleanings usually aren’t worth the money because the extra savings you get from cleaning your panels is unlikely to make up for the cost of the cleaning. In most cases, you can just let rain clean your solar panels naturally.

However, in certain parts of the southwest and California, occasional solar panel cleanings may be worth it. Solar panels in these areas have higher power losses due to soiling and, especially in California, electricity is pricier. A cleaning every year or two may actually save you money.

Key Takeaways

  • Rain does a good job of naturally cleaning solar panels, as long as they’re mounted at a tilt angle of 10 degrees or higher.
  • Professional solar panel cleanings will increase your system’s power output, but they may not always be cost-effective as it depends on factors like soiling losses and energy prices.
  • Some cleaners claim an instant 20-25% increase in power output, but based on our testing we believe that most homeowners are likely to see closer to a 5-10% increase.
  • You can clean your solar panels yourself to save money. However, weigh the potentially minimal power gains against the risk of climbing on your roof. Be sure to research how to do it safely beforehand, since doing it incorrectly could damage your panels.

How Much More Power Do Clean Solar Panels Output?

Many solar panel cleaners tout an impressive 20-25% boost in power output post-cleaning. It’s a bold claim, one I had to put to the test. So, I rolled up my sleeves and set up an experiment where I tracked the power output of three solar panels, each at varying levels of dirtiness.

Here’s a quick rundown of the results:

  • Panel 1 (Least Dirty): Before cleaning, it was at 84 watts. Post-cleaning? A slight nudge to 86 watts, just a 2.4% increase.
  • Panel 2 (Dirtier): This one started at 83 watts and climbed up to 92 watts after cleaning, marking a 10.8% increase.
  • Panel 3 (Dirtiest): Initially at 82 watts, it jumped to 93 watts post-cleaning, a 13.4% increase.
PanelPre-Cleaning Power OutputPost-Cleaning Power OutputIncrease
184W86W2.4%
283W92W10.8%
382W93W13.4%

Based on these results, the average increase across all panels was about 8.9%. Now, let’s be clear: seeing a 20-25% increase, as often advertised, seems pretty unlikely unless your panels are extremely dirty. And remember, the increase in output is temporary; panels begin to accumulate dirt right after cleaning.

If you’re pondering whether to hire a solar panel cleaner, expect a more modest bump in power output than the often-quoted 20-25%. Based on my test, I’d say 5-10% is more realistic.

How Much Money Could a Solar Panel Cleaning Save You?

When it comes to solar panel cleaning, the million-dollar question (or should I say, the couple-of-hundred-dollars question) is: how much can it actually save you? Let’s break it down with some numbers and a real-life scenario.

According to the National Renewable Energy Laboratory (NREL), average soiling losses range from 4.3% to 7.5%, with many studies confirming around a 6% loss per year.

Let’s take an example of a typical household whose solar system saves them $2,000 annually on energy bills. Assuming these savings already factor in a relatively high soiling loss of 7%, the panels, if kept immaculately clean all year, could save an additional $150 annually ($2,000 divided by 93%). But, remember, panels start collecting dirt right after cleaning, so the actual savings would be less.

How Much Does a Solar Panel Cleaning Cost?

From quotes I’ve seen shared online, prices typically range between $200 and $400. But this can vary based on your location, the number of panels, and their accessibility.

Cleaners typically charge a per-panel fee of $5-15 with some extra flat fees built in. Always consider getting multiple quotes to ensure you get the best deal for your specific needs. Don’t let some scrappy young kid overcharge you.

When Getting Solar Panels Cleaned Is Worth It

Deciding whether to pay for a cleaning hinges on a few key scenarios. In the US, it generally makes sense if you’re in a region with high energy prices and soiling losses, like California. There, the combination of minimal rainfall and high electricity rates can justify the expense every year or two.

It may also make financial sense in southwestern states like Arizona and Nevada, which also have high soiling losses according to SolarAnywhere.

Lastly, if your panels are mounted horizontally, then rain doesn’t do a good job of naturally cleaning them. So, regardless of where you are, if your panels are mounted flat, then regular cleaning will likely be needed. Case in point: Google cleaned some flat solar panels at their campus and reported an instant doubling in output.

But, the places where cleanings make the most sense aren’t even in the US. Saharan Africa, the Arabian Peninsula, and parts of the Middle East all have incredibly high average soiling losses. If you’re in one of these regions, or even parts of India and Australia with similar conditions, regular cleaning could significantly impact your solar system’s production.

Of course, you can also clean your solar panels yourself. It’s a cost-effective approach, especially if you’re comfortable with the risks of climbing on your roof. For occasional needs, like during pollen season, even spraying your panels with a hose can make a difference. Just be sure to do it early in the morning to avoid thermally shocking the glass on the panels.

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Alex Beale
Alex Beale
Alex Beale is the founder and owner of Footprint Hero. As a self-taught DIY solar enthusiast, Alex has spent 4 years producing educational solar content across YouTube, TikTok, Instagram, and the Footprint Hero blog. During that time, he's built Footprint Hero to over 7 million blog visits and 18 million YouTube views. He lives in Tennessee.