Do I Need to Clean My Solar Panels?

As our EcoSmart homes are built with solar panels, we get asked this question quite a bit. The answer to this life mystery is, it depends. We know, that’s not what you want to hear, but the need to clean your solar panels really does depend on the circumstances along with the outdoor elements. In some situations, rain or snow may clean most of the dust buildup. In other conditions, the snow and dust could do more harm than good. In both dry and humid climates, environmental factors, different types of dust, the location of your home, and installation factors will all influence how often you clean your panels. In this blog, we go through your questions about solar panel cleaning.

Is the Rain Enough to Clean My Solar Panels?

In a study conducted in Spain, researchers measured an average performance reduction of only 4.4% after a year’s worth of dust buildup. That doesn’t seem too bad, right? But the study also found that in “long periods without rain, daily energy losses can be higher than 20%.” This means that in a dry climate where dust buildup is common the problem remains. A lack of rain results in dust buildup that can get progressively worse the longer the dry spell lasts.

Meanwhile, places with normal rainfall can rinse away dust and keep your solar panels producing around 95% of their maximum capacity. Knowing this statistic might lead you into thinking that more rain equals less solar maintenance. That’s not completely true though. Most of the time there’s more to the scenario than dust alone. Pollen, bird droppings, leaves, ash, and haze can form when smog or smoke hangs heavy in the atmosphere. These all combine to create a layer of surface soiling, which may or may not wash away in the rain. Here’s a report from Renewable and Sustainable Energy Reviews that digs into the many complex variables involved.

In the case of rain, research concludes that allowing rain to do the work of cleaning solar panels is a fine decision, only if you live in the right kind of environment where…

  • Dust makes up most of the buildup that forms on solar panels.
  • The makeup of the dust will effectively wash away with the rain.
  • It rains with the right frequency to keep dust buildup from depleting your solar energy production.

How Do You Know When it’s Time to Clean Your Panels?

With a little bit of experience monitoring your solar panels, you’ll learn how much fluctuation to expect over the course of a year. During the summer, you’ll have more energy, while in the winter, the sun’s not out for long, so your solar energy isn’t as high. If you start noticing a continuous reduced output at a time when the weather is nice and bright, dirty panels could be the culprit. 

Okay, My Panels Are Dirty. How Do I Clean Them?

Cleaning your solar panels shouldn’t cost an arm and a leg, nor should it be a complicated chore. If possible, spraying your panels off from the ground with a hose is the easiest and best route. But the stickier the buildup, the more likely it is that you’ll need cleaning tools and supplies to wipe the buildup correctly. Pick a soft scrubber, squeegee, or brush, that won’t scratch or damage the panels. Choose a very mild soap that doesn’t contain any chemicals which could harm or degrade the panels. From there, here’s how you clean the panels:

  • Fill a bucket with warm water and add a small amount of mild soap.
  • Rinse your solar panels with a hose, or with another low-pressure sprayer.
  • Use soapy water and the scrubber to gently scrub the panels and clean them of any debris or buildup.
  • Rinse solar panels thoroughly to remove any soapy water.
  • Allow panels to dry in the sun.

Lastly, you should never clean your solar panels during the hottest part of the day! The extreme temperature difference between the water and the solar panels may cause the glass to crack.

Final Words

Depending on your weather conditions, dust, and other pollutants can accumulate on your solar panels. It’s important for you to regularly rinse off your panels. If necessary, follow the tips above to carefully clean them, or hire professional cleaners. If done correctly, cleaning your solar panels will keep your system operating at maximum efficiency so you can reap the full benefits of going solar all year long!