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How To Wash & Clean Solar Panels

You already know that switching to solar power for your home or business is a great way to save money and is a better choice for the environment.

However, there’s more to having panels than just sticking them up on your roof and hoping for the best.

Regular cleaning and maintenance can keep your solar panels operating at peak efficiency 24/7 and extend their life span.

If your solar panels are caked with grime, dirt, bird feces, or other substances, they won’t work as effectively. That’s why it is so important to have a schedule for monitoring and cleaning yours.

Not sure where to start or how to handle the task?

Solar panels cleaning is normally a do-it -yourself project because the cost of a third-party cleaning them typically exceeds the energy savings.

Learning how to clean solar panels isn’t as difficult as you might think. In fact, if you know how to clean a glass window or mirror in your home, you can tackle the process easily.

Here’s what you need to know about cleaning and maintaining your solar panels.

Do Solar Panels Need to Be Cleaned?

So, you’re probably wondering whether it is actually necessary to clean solar panels. 

The answer is yes. Solar panels need periodic cleaning to operate at their best.

Think of all the different elements that can buildup on your solar panels.

Just letting your panels sit and hope that some large storm is going to come and clean them for you isn’t going to do the job, either.

Energy losses are usually low but can be as much as five percent if the area you live in doesn’t get a lot of moisture within a given year.

And that means you’re paying more for energy costs than you really need to be.

Why doesn’t occasional rain do the trick?

The reason is that rain only handles so much actual coverage of the surface of the panel at one time. Plus, there is a lot of debris and dust within rainwater itself. Think of a dirty window after a rainstorm that doesn’t fully get sparkling clean.

This is a good example of why relying on precipitation alone isn’t a wise idea and why you need to make an effort to clean your solar panels on a schedule.

how to wash solar panels image

What Is the Best Way to Clean Solar Panels?

There are numerous ways you can clean your solar panels, but the easiest is with just warm water and dish soap.

If your panels are up on your roof, you might need a partner to help you hold the ladder and bring two buckets up there. One should be filled with the soapy water and the other with clean water.

Dip a microfiber cloth in the soapy water until it is submerged. Gently clean the solar panels with the soapy rag before wiping it a second time with an additional rag covered with clean water.

Wash and rinse.

Finally, dry each one with a third towel. If you have to make a couple of passes to get everything off, that is okay.

You can also use a soft squeegee, as well. Just be sure to avoid any cables and the underside of the panels.

As a side note, if you have hard water in your area, you might consider investing in a water softener. The minerals in water that comes from your faucets can leave spots on the panels and may interact with the frame and cause corrosion.

Does Cleaning Your Solar Panels Make a Difference?

Yes, cleaning your solar panels on a regular basis can make a difference in your system’s power output and help extend the life of your solar panels.

However, any increases in power output depend on how dirty they get and the angle at which the solar panels are installed. Those on a flat roof or patio often have a larger amount of buildup that stays in place after a rainstorm.

Panels installed at steep angle don’t usually see much of a change in output after a good scrubbing. Gravity helps to keep them cleaner.

The data on whether solar panels perform better after cleaning remains spotty at best (pun intended). Some people report little additional energy production while others report increases as high as five percent.

Why a range of results? It often has to do with the area of the country you live in and the amount of rain you receive. Plus, the type of terrain surrounding your neighborhood can have a big impact, too.

What we do know for sure really comes back to common sense. A dirty panel doesn’t get as much direct sunlight as a clean one, therefore it doesn’t work as well.

Again, let’s use the analogy of a dirty window. Do you get as much light in your home on a summer afternoon when the glass is perfectly clean or when there’s a film on the surface?

As you can see, clean solar panels are just an altogether better choice.

Can You Use Windex on Solar Panels?

One question a lot of solar panel owners want to know is if it is possible to use glass cleaner on solar panels. In most cases, yes. Windex is safe enough to use on most solar models but beware of off-brands or those that have extra additives or perfumes. For this job, the old-fashioned kind with a blue tint is the optimal choice.

However, commercial glass cleaners shouldn’t be the first thing you grab when looking to maintain solar panels. Mild dish soap and water is usually the recommended option, as detailed above. This will keep you from getting streaks and is often the most ideal way to clean solar panels without damaging them.

Also, avoid other chemicals you’ve got around the house for cleaning. Certain ones contain bleach and ammonia, which aren’t good for the panels themselves.

You’ll also want to avoid that home remedy for cleaning windows with vinegar or any other cleaning hack you might find on the internet. Again, regular soap and water are still best.

How Often Should You Clean Solar Panels?

Getting up on your roof and cleaning your solar panels isn’t always an easy task. However, having a routine to keep them clean is important for overall efficiency, power output, and extending their life span. But this often depends on where you live and the type of weather you have.

If you rarely get rain and live in a dusty location, you’ll likely need to clean your solar panels once a year at a minimum and once a quarter at best.

Those in areas where it rains more often or where panels are at a thirty-degree or higher angle can probably just get away with once a year.

You’ll also need to look at the area around your home to determine how often to clean solar panels. If your neighborhood is surrounded by agricultural land or open fields, you’ll likely need to clean them much more frequently than someone who doesn’t have this issue

Have an unusual number of birds due to feeders in your backyard? Sadly, this might mean you’ll have to get up on your roof and do a bit of scrubbing on occasion. It really just depends on your unique situation.

Will Cleaning My Solar Panels Increase Efficiency?

As we’ve mentioned above, whether you’ll see an increase in efficiency for your panels highly depends on how dirty yours become during normal conditions.

If you haven’t cleaned them at all or you don’t get a lot of rain where you live, there’s a good chance you’ll see a small jump in production after that first cleaning.

If you’re climbing up onto your roof once a month to keep your panels pristine, you probably won’t see much of a jump between cleanings as they’re usually in prime condition anyway.

Realistically, monitoring the output of your solar panels regularly is key.

Monitoring shows if there’s an issue that causes any decrease in output, which may indicate dirty solar panels, shading for the time of year, or that system performance issues exist.

Should I Hire Someone to Clean My Solar Panels?

This is a commonly asked question, as there are a lot of companies out there and on social media advertising that they clean solar panels.

The main concern you should ask yourself if you’re thinking of hiring the job out to someone is this: how badly do you want to keep your feet on the ground instead of getting up on your roof?

For most people, the thought of climbing a ladder and doing all that works sounds like a pain. Those people don’t mind paying to have someone do it for them, which is perfectly fine.

Solar panels cleaning is normally a do-it -yourself project because the cost of a third-party cleaning them typically exceeds the energy savings.

The truth is that cleaning solar panels isn’t any more difficult than cleaning windows and most people do a wonderful job even without experience.

Wrap Up: How to Clean Your Solar Panels

The main takeaway here is that you should consider cleaning your solar panels periodically. Buildup including dust, debris, and animal excrement can all cause your power output to decrease. Instead, it is better to have a plan to keep your panels in prime condition by using a bit of soap and water.

Keep good care of your solar energy equipment will go a long way to maintaining peak efficiencies and extending the life of your equipment.

Should you desire or require, we provide solar power systems analysis, design & sales, energy monitoring & alert system, and solar panel or inverter repairs.

President at Jamar Power Systems
Phil Edwards is President of Jamar Power Systems. With over 30 years of electrical contracting experience, his companies have wired over 30,000 housing units, including 1000's of residential solar installations. His company is a member of WECA and BIA.
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