How To Clean Solar Panels: A Step-By-Step Guide

If you invest in solar panels for your home, you will want to do everything you can to ensure they’re as efficient as possible.

One of the easiest ways to maintain your solar panels is to ensure that they’re clean. If dirt, dust, and debris are allowed to accumulate on the surface of your panels, they will affect their efficiency and potentially limit their productivity.

But is it really necessary to regularly clean solar panels? And how do you safely clean your panels without calling a professional cleaning company?

We answer these questions and explain how to keep your solar panels clean in this guide. But let’s first remind ourselves of how solar panels work and why it’s important to keep their surface free from dust and dirt.

How do Solar Panels work? 


Whether roof or ground-mounted, solar panels work by receiving light into their solar cells. The more sunlight that a panel can receive, the more power it will generate. (Related: Home Solar Panel Installation Cost & Consumer Guide) If your solar panels are dirty, the cells will be less efficient as they won’t be able to receive as much sunlight as they would if they were clean.

Do I need to Clean my Solar Panels? 


An interesting study from Duke University researchers found that dirt, dust, and pollution can reduce the efficiency of solar panels by up to 25%. The researchers were concerned with monitoring how effective dirty solar panels were and found that the build-up of dirt, dust, and debris over just a couple of weeks blocked much of the sunlight from reaching the panels.

Remember, your solar panels need to be directly exposed to sunlight in order to produce power. As the Duke research exemplified, if your panels are covered in dirt or dust, they are bound to be less effective. For homeowners in certain states, regular rainfall may be sufficient to keep panels relatively clean and free from pollutants, dirt, and debris.

But for others, particularly city-dwellers who live in areas with high levels of smog and those living out in the desert with sand swirling around their panels regularly, routine cleaning is a vital step in the ongoing maintenance of solar panels.

How often should I Clean my Solar Panels? 


Again, how often you clean your solar panels depends on where you live and how dirty they become. Some installers recommend that you clean your solar panels once every six months, but this might not be necessary if you live in an area with heavy rainfall. Equally, if your panels are exposed to large amounts of smog or sand, you might need to clean them every couple of months to ensure they’re functioning well.

A Step-by-Step Guide to Cleaning Solar Panels


If you’ve decided that you want to clean your solar panels yourself, you can do so by following the simple steps listed below:

Step 1: Turn off your System


Although your panels are water and weatherproof, it’s best to turn off your system before undertaking cleaning and maintenance. You can follow the instructions listed in your manual to find out how to turn off your system safely.

Step 2: Remove Debris and Dirt


Begin by removing any debris like fallen leaves and twigs from your panels. Then, with a soft brush, remove as much dirt and dust as you can without wetting the panels, as this will make your life easier during the steps that follow.

Step 3: Wet the Panels


Using a garden hose, spray the front of your panels evenly. Be mindful of the pressure of your hose, and don’t set it too hard, as doing so can cause damage to the panels.

Step 4: Wipe with a Soft Cloth or Windshield Cleaner


Once your panels are wet, wipe them with a soft cloth or standard windshield cleaner. At this stage, you might need to use some warm water to remove stubborn pieces of dirt or bird droppings, but you should avoid using soap or detergents.

Step 5: Respray your Panels


After you’ve wiped your panels, respray them with the hose and remove any bits of debris that are still clinging to the surface. Again, make sure the pressure of your hose isn’t too high.

Step 6: Leave them to Dry


Leave your panels to air-dry for a few hours. You can also remove excess water if you wish, using a squeegee with a fitted rubber blade. Once your panels are dry, you can turn the system back on.

Key Considerations when Cleaning your Solar Panels


The most important thing to remember when cleaning your solar panels is not to damage them. Scratching or damaging the glass will render your system ineffective, so you need to be diligent when cleaning your panels. Here are some important considerations before and during the cleaning process:

  • Don’t use soaps or detergents. You should never use soaps, detergents, or powders when cleaning your solar panels. These products can leave a film layer on the surface of your panels and may affect their efficiency. Instead, warm water and a soft cloth should be sufficient to remove any stubborn dirt from your panels.
  • Take care when cleaning roof-mounted panels. It might seem like an obvious point, but if you climb up onto your roof to clean your solar panels, you need to be careful! Make sure your ladders are firmly fixed, and you have a stable footing before attempting to clean your panels. The last thing you want to do is injure yourself while you’re up on the roof.
  • Avoid cleaning panels when they’re hot. The best time to clean your solar panels is early in the morning when they’re not overly hot. Cleaning your panels with cold water during the heat of the day could cause the glass to crack due to the sudden temperature change.
  • Only clean the surface of your panels. Be careful not to soak the backs of your solar panels as you may cause damage to the wiring. When applying water to the panels, you only need to wet their surface.
  • Don’t use a pressure cleaner. Using a pressure cleaner on your solar panels is likely to do more harm than good. Instead, opt for a standard garden hose with low to medium pressure and gently clean the panels with a soft cloth.

Cleaning Solar Panels: Frequently Asked Questions (FAQs)


Can I hire someone to clean my solar panels?

If you don’t want to clean your solar panels yourself, you could always hire a professional company to clean them on your behalf. But be mindful that installers tend to charge a lot of money to clean your panels, so make sure you weigh up the pros and cons before engaging their services.

Will rainwater clean my solar panels?

While rainwater will remove surface-level debris and dust from your solar panels, it won’t effectively clean your panels. Think about how rainwater affects your car windshield for a minute. Outside the range of your wipers, there is always a film of dirt and debris that affects visibility through the windshield. If you rely on rainwater alone to clean your panels, they will never be truly clean, and a small layer of dust particles will affect their ability to receive sunlight.

If I don’t clean my solar panels, will they still work?

Some homeowners don’t bother cleaning their solar panels and find that they still generate sufficient energy for their homes. But, as we’ve mentioned, cleaner panels work better than those covered with dirt, sand, and pollutants, so cleaning your panels once in a while will undoubtedly improve their efficiency.

Do I need to remove snow from my solar panels?

In most instances, snow will slide off your solar panels as it melts. However, you could always use a snow rake to remove any excess snow from your panels. It’s important not to use a standard broom or shovel as you could damage the glass that protects the panels.

Can bird droppings ruin my solar panels?

It’s pretty much impossible to protect your roof-mounted solar system from bird droppings. If you can see that some of your panels are covered in bird droppings, it’s a good idea to get up there and clean them, as the poop prevents your panels from doing their job to their full capacity. Also, the longer droppings sit untreated, the harder they will be to remove.

Conclusion 


There’s no hard and fast rule when it comes to cleaning solar panels. But that being said, removing dirt, dust, and debris from your panels will undoubtedly improve their performance and increase the amount of power they are able to generate.

If you live in an area with high levels of smog or sand particles in the air, it’s a good idea to clean your solar panels every couple of months to guarantee their efficiency. The good news is that you can easily clean your solar panels with water and a soft cloth, so you don’t need to invest in expensive cleaning materials or a professional cleaning service.

Just be careful not to damage the surface of your panels during cleaning, so avoid soaps, detergents, and pressure washers that are likely to do more harm than good.

Kenneth Wilson
September 10, 2021
Contractor Tips, Solar

Kenneth Wilson

Retired contractor. Currently residing in Southwest Florida. Now in semi-retirement, I write and manage this blog focused on helping home owners make savvy decisions when it comes to finding contractors and getting their projects done.