Is Solar Panel Cleaning Necessary?

If you have a solar energy system or solar photovoltaics (PV) array at your facility or home, you know how much money solar panels can save you on your energy bill if they’re working the way they should be. What you may not realize is a dirty solar panel can cause performance levels to drop. Dirt and dust buildup can affect the energy output of a solar panel. A clean solar panel operates at maximum efficiency and protects your investment.

Do solar panels need cleaning? 

Yes, your solar system needs to be clean in order to operate at optimal performance. Regular cleaning is a key component of solar panel maintenance.

In a study published in Renewable and Sustainable Energy Reviews, researchers found that accumulated dust on solar panels affects the amount of energy delivered from a solar PV array on a daily, monthly, seasonal, and annual basis. 

After a three-month test on solar panels located in an industrial area near a railroad in Boston, Massachusetts, scientists found an average of 1% of power loss from dust accumulation, with the highest degradation at 4.7%. 

In another study done in California that looked at about 200 solar panel arrays, annual losses due to dirty solar panels ranged from 1.5% to 6.2%.

How to clean solar panels?

You have three options when it comes to cleaning solar panels. You can do it yourself, hire professional cleaners, or install a self-cleaning system.

Doing it yourself can be a tedious and dangerous undertaking depending on where the panels are located and how difficult it is to get to them. A solar cleaning service should be able to get the job done properly, but if you do hire a professional panel cleaning service just make sure they don’t use abrasive cleaners that can damage your solar panels.

A self-cleaning system is one of the best ways to ensure your solar installation is working the way it should be. An automated cleaning system takes care of the cleaning for you and you’ll be able to set it to clean as often as you would like. Your panels will almost always be free from dust and debris. An automated solar cleaning system also uses less abrasive materials and methods than traditional cleaning methods and can increase your energy production by up to 30%. Learn more solar panel cleaning tips here.

Should I hire someone to clean my solar panels?

In some cases, you may need to hire a professional solar panel cleaning service to clean your solar installation. This might be the safer and easier option. 

Professionals have insurance and more than likely can guarantee their cleaning services, unlike yourself in the case of home solar or maintenance staff in the instance of commercial solar. Your solar panels may be in a hard-to-reach spot or on a roof that is too high, steep, or otherwise dangerous for your staff to tackle. A self-cleaning system provides a more economical option when you start to add up the costs of hiring professional cleaners, which means a quicker ROI for you. 

How do you clean solar panels yourself?

You will need a hose, a bucket of soapy water with mild soap, like dish soap, a soft scrubber or sponge, and a squeegee. Do not use a pressure washer, harsh chemicals, or abrasive scrubbers, which can damage your solar panels and solar photovoltaic cells. Homeowners and commercial maintenance crews often ask about pressure washing their solar system since it seems like a logical option for cleaning but it is best to leave pressure washers for exterior cleaning, like the roof or gutters.

  1. Fill your bucket with water and a little soap (don’t put in too much).
  2. Gently hose off your panels.
  3. Soak your soft scrubber or sponge with the soapy solution and use it to clean off the panels.
  4. Hose off the panels again making sure to get rid of any soap residue.
  5. Repeat until the panels are clean.
  6. Squeegee the panels dry trying your best to not leave any streaks.

Does self-cleaning solar panel technology really work?

Something else to consider is an automated solar panel cleaning system. Instead of periodically cleaning your panels, you can fully eliminate soiling losses by investing in a system that can conduct regular cleaning at increased intervals, such as weekly or monthly.

Keeping your array clean often can increase your energy production by up to 30%! Sometimes a cleaning crew can cause damage to your panels through their use of abrasive cleaners or hard water, which can void your warranty on the installation. 

We’ve discovered a fully automated cleaning system that has a patented feature of purifying the water used to clean your panels from limescale. The water from the system is applied through drip irrigation technology at low pressure at night, which avoids potential cracking of the solar panel glass if cold water is applied during warmer temperatures. 

On top of that, the system has an app that allows you to remotely clean your array and notifies you of faults.

Does rain clean solar panels?

Depending on the environmental factors of where your solar panels are located, rain can be an effective way of cleaning solar panels. In the above-mentioned study of California solar installations, after a slight rain, the efficiency of some of the solar panels declined sharply, while the performance of some of the panels improved. 

According to the researchers of the study, a rainfall of at least 20mm is needed to adequately clean solar panels and ensure optimal solar output.

The National Renewable Energy Laboratory’s (NREL) Best Practices for Operation and Maintenance of Photovoltaic and Energy Storage Systems report finds heavy rains can completely clean solar panels, while light rains can have the opposite effect or make soiling and dust buildup even worse.

NREL suggests solar arrays in areas where there are frequent heavy rains don’t need to invest in a cleaning regimen, but special conditions require a cleaning schedule. According to NREL, sources of soiling that may indicate the need for frequent solar panel cleaning include:

  • Construction dust
  • Pollen
  • Bird populations
  • Diesel soot (i.e., bus depots)
  • Industrial sources (i.e., cooking or manufacturing)

It should be noted, if you live in an area where it snows you should clean your solar energy system after heavy snowfall. Snow buildup can create a dirty panel and decrease energy output. Make sure to use lukewarm water. If you use very warm water or even hot water to clean it can cause the glass of a solar panel to crack.

How important is it to keep your solar panels clean?

Having clean panels ensures your solar array is working at maximum efficiency and maintains their life. A decreased energy bill and less reliance on your utility provider are just some of the reasons why regular cleaning and regular maintenance of your panels are important. 

Taking a few steps to ensure your solar panel system is in tip-top shape ensures you’ll reap the benefits of solar power for years to come! 

Have questions about a solar PV system installation or want some guidance on the best self cleaning solar panel technology? Please reach out to one of our experts so we can help.