Home Solar Panel Cleaning Tips & Checklist
"Do solar panels require regular maintenance or cleaning?"
We get this question a lot. And luckily, the quick answer is no. Nature does the bulk of the work for you, but a quick cleaning once or twice a year, may help your system perform at its peak potential.
Here are some tips for determining when and if you should clean your solar panels, how to clean your panels, and when it's time to call in professional help.
Why Do Solar Panels Need to be Cleaned?
Panels covered with too much dirt or debris may begin to produce less power.
In most cases, the loss of power isn't significant — maybe 1 to 4.7 percent. But one study found that long-term dirt buildup can reduce a solar panel's electricity production by as much as 25 percent.
The good news is that seasonal rain and snowmelt usually wash off dirt or animal droppings that may have accumulated. But if your area receives very little precipitation and has dusty, windy weather, your panels may need to be cleaned occasionally. Some homeowners are confident washing the panels themselves, others choose to have them cleaned by a professional.
How Do I Know When My Solar Panels Need Cleaning?
Do a monthly visual inspection to look for any noticeable dust buildup. Also, you can watch your electric bill or check your solar system monitoring app for any noticeable drop in production. Only then should you worry about cleaning your solar panels. And even then, nature is most likely going to clean them for you.
What Should I Use to Clean My Solar Panels?
Fortunately, cleaning solar panels is easy for ground-mounted systems and for some rooftop solar systems on a typical one-story house. People commonly use a hose and a soft-bristle brush with an extended handle, like the type used to clean off an RV or truck. Water is usually enough, fingerprints, stains, or accumulations of dirt on the glass may be removed with over‐the‐counter glass cleaners, or with a 3% soap‐and‐water solution.
If the panels are hard to access, high-pressure hose nozzle with an attachment that holds the cleaning solution may work. These can be found at a local home maintenance store. Find a safe place to stand, spray soapy water on the panels and then thoroughly rinse them off. It's really that simple.
Before you decide to wash the panels on your own, you should see what's covered by your solar service provider. With many leases, the cleaning is free of charge, and if you own, you need to make sure to you don't use tools or cleaning practices that void your warranty.
When should I Call a Professional?
Just like washing your car or cleaning your home, you can hire a professional to clean your solar panels.
If you have a rooftop system, it may be a good idea to call a professional cleaning service. In addition to the convenience of not climbing up on the roof yourself, professionals are properly equipped for rooftop safety. Whenever hiring a professional, you should check to make sure they are licensed and bonded. For ground units, it may not be worth the service fee since you can safely clean your own panels with a simple dose of hose water and liquid soap.
How Often Do Solar Panels Require Cleaning?
Again, nature may take care of the routine cleaning for you. But keep an eye on your monthly electricity bill or monitoring app. If you see a noticeable drop in production, it might be time for a quick clean. As a general rule, cleaning your system about twice a year should be sufficient.
If you live in the western United States where wildfires are annual occurrences, be sure to check your solar panels for ash or soot build-up after nearby fires have been safely contained. Since they are different from typical dust or animal droppings, you may want to contact a professional to find out the best way to clean them from soot build-up.
What Does it Cost to Clean Solar Panels Professionally?
Thumbtack quoted over a million professional solar cleanings in 2020 and found that the national average cost is $130.*Prices will vary by company. This national average comes from over a million cleaning quotes from Thumbtack.com. Prices will vary by zip code, number of panels, and the accessibility of your system. Check with your installer for cleaning company recommendations. Many professionals charge by the panel or hour. The average 32-panel system typically takes up to 2 hours for professional cleaning. That said, prices and time required vary based on a number of factors, such as your zip code, number of panels, roof pitch, and the accessibility of your system. Check with your solar provider to see if they can clean your panels or if they can provide a recommendation for a company that can do this for you.
What Should I Avoid Doing to My Solar Panels?
Before you do anything, here are a few things you should not do:
As a general rule, stay on the ground. Nobody should get up on your roof without a secure ladder and proper fall protection equipment. We highly recommend hiring a professional if there's a need to go on the roof for panel cleaning.
Avoid using hard or mineral-rich water. It may damage panels over time. If your area only has hard tap water, you can buy an inexpensive water-softening hose attachment to filter out minerals. Otherwise, you can use distilled or de-ionized water.
When using a high-pressure water nozzle, don't get close to the panels. While they're extremely durable, you don't want to risk any potential damage.
Don't use abrasive brushes, pads or powders. Instead, choose soft-bristle brushes, towels, and squeegees if necessary.
What's the Best Way to Clean My Solar Panels?
Window cleaner or 3% soap‐and‐water solution (optional)
Soft-bristle brush or squeegee (like those used on tucks & RVs)
30 min – 2 hrs (dependent on the system size and accessibility)
1 – 2x per year (dependent on weather conditions)
Cost to hire a pro:
$133 (national average) *Prices will vary by company. This national average comes from over a million cleaning quotes from Thumbtack.com. Prices will vary by zip code, number of panels, and the accessibility of your system. Check with your installer for cleaning company recommendations.
In summary, here are the basic steps to cleaning your solar panels:
First, review your solar system and panel warranty to understand the terms and conditions, including any requirements related to cleaning. As stated above, if you are leasing your system, your solar provider may do this for you as covered by your maintenance warranty. If you have questions, discuss them with your solar provider before cleaning.
Stay on the ground or call a professional cleaner to do it for you.
Clean early in the morning or in the evening when the panels are cool. In high heat, water and soap can evaporate quickly, leaving streaks and smears.
To clean a module, simply wash the glass surface with softened, distilled, or deionized non‐heated water. Normal water pressure is adequate, but pressurized water up to 1500 psi may be used with caution.
If using a high-pressure water nozzle, don't get close to the panels. While they're extremely durable, you don't want to risk any possible damage.
Stubborn fingerprints, stains, or accumulations of dirt on the glass may be removed with over‐the‐counter glass cleaners, or with a 3% soap‐and‐water solution if necessary.
For smaller systems, wet the module glass with the cleaning solution and let it stand for five minutes. Then wet them again and use a soft sponge or seamless cloth to wipe the glass surface in a circular motion.
For larger systems, wet the module glass with the cleaning solution and let it stand for five minutes. Then rinse them with high‐pressure water or a soft squeegee.
Repeat once or twice a year or as necessary.
It's that easy. And if you're still looking into getting a solar system, visit our solar calculator to see how much clean energy you'll produce and money you'll save with SunPower's all-in-one home solar system.