How to Clean Your Solar Panels for Maximum Efficiency
Installing solar panels to your house or business not only reduces how much electricity is being generated(1) but also reduces your electric bill at the end of every month. Like any appliance or machine, however, solar panels need to be cleaned periodically to run efficiently. But how do you do that? Wouldn't getting a professional to do be safer? This article will answer any questions you might have on how to clean solar panels.
Should You Clean Your Own Solar Panels?
The simple answer is: Yes, you should. Like washing your car periodically will save the body from rusting, cleaning your solar panels will keep them running at full efficiency.
Since they're outside, pollen, dust, and grime have a tendency to build up and that covering of dirt and grime will pull your panels' working efficiency down by 15-25%(2). That means you'll be drawing 15-25% more electricity from your power company, which will reflect in your bill at the end of the month.
To show just how effective cleaning your panels can be, look no further than Google. In 2009, Google did a study on their panels at their solar farm in Mountain View, CA. It showed that when they cleaned the panels, they doubled their output in electricity(3). Furthermore, the same study showed that when solar panels are cleaned correctly, they worked 12% better than before.
Cleaning your solar panels takes about the same amount of time as cleaning your windows and you'll be putting more money back into your checking account. But can you do it yourself? Or should you get a professional? Let's look at both.
Cleaning it DIY...
If your panels are ground-installed, cleaning them yourself can absolutely be done DIY(4). If your panels are tilted, rain and snow will be able to wash off part of the grime. What cleaning solutions and tools to use to clean your panels will be covered in more detail later, but the easiest solution can simply be a hose, Dawn soap, and a soft rag or sponge.
However, it is important to remember if you clean your ground panels yourself, be extremely careful to not damage or scratch the glass. Even the tiniest scratch can deplete your panel's ability to draw in power.
...vs. Getting a Professional
What if your panels are installed on the roof, though? Can you clean them from there? You can, but there's a bigger risk involved. If you accidentally step on the panel, you can break or crack the glass, ruining it. Or if you trip, you can fall off the roof, which means a trip to the ER.
Getting a professional to clean your rooftop panels may be a bit more money, but it is cheaper than a hospital bill. Plus, if you have your solar panel system on a lease, most times the lease will cover maintenance costs(4). Additionally, many companies will do regular maintenance of their solar systems while others will do any repair work the customer reports.
Tools to Use
The only tools you will need to clean your panels are:
Air-hose system if you have one
Soft rag or sponge
How to Clean Your Own Panels
Cleaning your solar panels is actually very easy. Here are a few steps to get you started:
1. First, check with your solar panel manufacturer before you actually clean anything. They may have specific instructions on how to clean them.
2. Get up early or wait until close to dusk to clean the panels. If you wait until it is mid-day/afternoon when the system has been running a while, water droplets will evaporate and cause streaks, which can affect how well your panels continue working.
3. Try to simply hose off your panels first. Sometimes just the water will be enough to knock the layer of dirt off.
4. If not, then use a bucket of soapy water and a soft rag or sponge. Use a mild detergent and be careful how you scrub so you don't scratch up the glass.
Cleaning a roof system can be trickier. First determine what kind of system you have: is it just a few panels or is your entire roof covered? Do you have a flat enough roof to stand safely on? Or does it sharply slant? If you only have a few panels installed and your roof is relatively flat, then you could probably clean the panels the same way described above.
If it's the latter though, or you don't feel comfortable getting on your roof, then we suggest being safe and calling in a professional.
If you do plan on getting on your roof, this video(5) suggests getting a pair of skater shoes like Vans. The bottoms are built to grip a skateboard, which is similar to a lot of rooftops.
Make sure to clean any debris off the panels and check any connections.
Another tip is if you live in a snowy region and you need to scrape snow off your panels, buy a solar panel broom. Usually, you won't have to do this, but in case you do, the solar panel broom is built for panel glass. Don't use a regular broom or scraper; you'll end up scratching up the glass and decreasing energy production(4).
Homemade Solar Panel Cleaning Solutions
There are many solutions you can use to clean your panel system. But the easiest ways are by using an air-hose system or just hosing them down with water. If a little more elbow grease is needed, a bucket of soapy water will usually do the trick. But if that doesn't work or there's greasy spots, a non-abrasive solution will work too.
Here is a green one that doesn't involve any chemicals(6).
1/4 cup vinegar
1/2 teaspoon liquid non-abrasive soap or detergent
2 cups of water in a spray bottle
Drier regions will need to adjust the rations.
How Often Should You Clean for Maximum Efficiency
How often you should clean all depends upon where you live. Drier regions, like the Southwest, should probably clean once a month because of the dirt and grit being blown about. Southeast regions may not need that much cleaning depending on how much rain there is, but debris from trees will have to be cleared off periodically.
The best tip is simply to keep an eye on how dirty your panel system gets and set up a maintenance schedule around that.
To Wrap It All Up
To keep your solar panel system running at full efficiency, you will have to clean it periodically. How much you clean it will depend on where you live, but the actual cleaning is fairly easy. The most you should need is a hose, maybe some soapy water and rag or sponge if it's extra grimy or has stubborn spots. Be careful as you scrub though because you could scratch the glass and affect the energy production and output.
Ground systems can be easily cleaned by yourself. But if you have a full installation on your roof or you don't feel comfortable climbing up, call in a professional rather than risking a hospital bill.
Hopefully, this article has de-mystified the process of cleaning your solar systems and you can lower your energy bill even further by maintaining them yourself. Stay safe and enjoy!
 HowStuffWorks' article on solar panels  Energy Informative's page on how to clean solar panels  Google's study on cleaning solar panels  Energy Sage's page on cleaning solar panels  Westcoast Solar Energy video on cleaning rooftop solar systems  PurSolar and Energy page on cleaning solar panels