How to Clean Solar Panels (And Why You Should!)

How to Clean Solar Panels (And Why You Should!)

10 min read

A lot of people wonder whether it’s truly necessary to clean their solar panels at all.

After all, wouldn’t the rain wash it all away? Well… not really.

Over time, stubborn dirt and grime collect on and under solar panels. Think of leaves, twigs, and bird droppings. The problem arises when these things accumulate to a point where they eventually lower the energy output of your solar panels. Even worse – when they damage or wear out the solar cells.

Luckily, cleaning solar panels is easier than you think. Here’s a step-by-step guide:

  1. Shut down the solar system completely
  2. Brush off dust and any dirt
  3. Rinse the solar panels with mild soap & water
  4. Tackle stubborn dirt and grime with a gentle washcloth or sponge
  5. Give your panels a final rinse
  6. Let the panels air dry
  7. Hook your panels back up & turn them on

It’s possible to clean your solar panels in 15 minutes or so. With this article, I’ll teach you everything you’ll need to know. Including what materials to use and how often you should clean them. I’ll also offer some insight as to how to avoid damaging your panels (hint: it’s pretty easy, so stick around!).

First off, let’s start off with the basics:

 

Important Things to Know Before You Start Cleaning

When cleaning a solar panel, first, you should check the solar panel manufacturer’s recommendations for cleaning the panel. Here are some things you should know before you start:

 

Do you have to clean solar panels?

Yes, cleaning solar panels every once in a while is vital for them to work effectively. Mostly, solar panels accumulate dirt and grime on them over time, which will block sunlight from entering the solar cells. This will reduce the power that your panels generate. Leaving foreign residue, such as humid leaves or bird droppings, on the panels can also degrade them over time.

 

Benefits of clean solar panels

Clean solar panels have a lot of benefits. Here are some of them:

  • they produce more energy & work more efficiently
  • they maintain a warranty, as some companies make cleaning a condition for getting a replacement
  • they have a long a longer lifespan (when maintained)

 

What will happen if I neglect to clean my solar panel?

Every action has consequences, and thus failure to clean solar panels can cause a lot of harm. Here’s what will happen:

  • The panels will be less efficient by say 15-25%. This will mean less electricity, so you may have to source electricity from other methods.
  • Dirty panels can make you lose your warranty.
  • Failure to maintain panel cleanliness exposes them to more damage. For example, leaving residue on them may stain the panels and lower efficiency.

 

How to tell if your solar panels need cleaning

There are two ways that you can tell if your solar panels need cleaning:

  1. Physical inspection: Upon looking at your panels, you’ll be able to see dirt, dust, and other debris. Bird droppings, snow, and leaves are common offenders.
  2. Decreased production: Most solar panels come with a solar monitoring system that gives you a brief rundown of how well they’re performing. If you notice that your production decreases over time, it might be a sign that it’s time to clean your panels.

Note: If you clean your panels and this does not resolve the issue, you might have mechanical or electrical issues.

 

How often should you clean solar panels?

Your solar panels should be deep cleaned at least every six months. Late spring and autumn are the best times to clean them.

If you live in dusty and dry areas, like near farms or regions prone to air pollution like construction sites or industrial areas, you might need to clean your solar panels more often. You should try to do this at least every 3-4 months.

If your panels are relatively flat, you may have this issue as well.

 

How much does it cost to clean solar panels?

The average cost of cleaning solar panels ranges approximately between $150 – $330. This is an approximation because the actual cost will vary according to various factors like:

  • the height of your house
  • roof slant
  • where you live
  • the type of solar setup that you have

Of course, you can always clean them yourself – you’ll just have to be careful. This will cost approximately $25 to $50, depending on the supplies that you use.

 

Do I need to turn off solar panels to clean them?

When cleaning your solar panels, the first step you should do is to completely shut down the DC system. This is located inside the combiner box. This step is vital, as it ensures your safety and prevents the solar panels from getting damaged with water (while DC electricity is still flowing).

The AC system should be shut down using the solar supply main switch.

 

How to stay safe when cleaning your panels

  • Mostly, for solar panels mounted on the rooftop, professional help should be sought, as it can be risky.
  • Pick a cool day to clean your solar panels. Solar panels can become very hot in the sunshine. Early morning cleaning is recommended, as the panels would have had time to cool overnight. It’s also safer for you. You’ll be less likely to get sunburned 0r to suffer from dehydration.
  • Safety measures should be adhered to first before cleaning; this includes shutting down the system completely.
  • When washing, if you see a cable that is damaged, you should immediately stop and seek professional help.
  • Solar panels mounted on the roof are best cleaned from the ground; if not accessible; do not attempt to climb up.
  • Use of a garden hose with a much-regulated pressure is recommended to prevent water from going into the junction box.
  • When washing, ensure water is directed towards the top of the panels only.

 

Things to avoid while cleaning your panels

  • Avoid using harsh detergents, soaps, and powders as they may leave a thin film on the surface, which may impact the panels’ efficacy on light absorption.
  • Avoid washing the solar panels when heated, as a sudden change in temperature may cause a crack on the glass that protects it.
  • Avoid cleaning the solar panels by yourself if you don’t have the knowledge or experience to do so; instead, contact a cleaning company to wash them for you.
  • Avoid climbing onto the rooftop to wash the panel, unless it is unavoidable. Don’t put yourself in a position where you may fall.
  • Avoid grabbing onto the backs of the panel or in the gaps between the panels and your roof. This is where the wiring is typically located and it may cause damage.
  • Avoid cleaning the solar panel with a pressure cleaner, as the extreme pressure produced by it can destroy the panels.

 

Do you need a license to clean solar panels?

Cleaning your solar system at home doesn’t need any sort of licensing, as this is not for business purposes. However, for a person who does solar cleaning as a business, they will need a license showing they have a permit and are certified, and have knowledge of cleaning the solar panels.

 

Does rain clean solar panels?

Rain can clean solar panels, but only to an extent. It is effective for rinsing off fine dirt and sand. However, every so often something sticky may get on your panels, such as gummy fruits or bird droppings. In these instances, you will most likely need to clean the panels yourself.

 

 

Cleaning Solar Panels: Materials to Use & Avoid

Here’s some information on what you should or shouldn’t avoid when cleaning your solar panels:

 

Can you use soap to clean solar panels?

Yes and no. Some types of soap can damage the glass, while others are mild enough to not cause an issue. When washing, a combination of warm water and dish soap is preferable.

However, some solar companies discourage the use of soap because they say that it leaves a residue that shades the panel, just like the dirt that was washed off. Certain soaps are also said to encourage the fast buildup of dirt because it causes stickiness on the panel surface. This is why dish soap is preferred (in the event that you don’t have anything else to clean it with).

 

Can you use a pressure washer to clean solar panels?

No, using a pressure washer to wash solar panels is not advisable at all. This is because the pressure might force water into the panels’ junction box or the solar plugs that are not sealed well and exposed wires. Generally, it is recommended that even when using a hose, the pressure should be maintained below 40bar.

 

Can you use vinegar to clean solar panels?

Yes, vinegar can be used when cleaning solar panels. Vinegar is a naturally-occurring, safe product and is excellent for cleaning glass solar panels. A mixture of vinegar, water, and mild soap can be a very effective solution for cleaning solar panels.

 

Can you clean solar panels with Windex?

When cleaning solar panels, it is essential to follow the manufacturer’s guidelines, as different manufacturers use different treatments on their panel covers.

It is not recommendable to use Windex and other abrasive cleaners to wash your solar panels, as they are made with additives such as detergents and other coloring matter. These additives might leave a residue that could potentially degrade light absorption.

 

Can you clean solar panels with tap water?

Solar panel manufacturers recommend washing solar panels using de-ionized or distilled water. If you stay in an area where there is hard tap water, it is advisable to purchase a hose attachment, which helps filter minerals out of the water.

Using hard water, that is rich in minerals can damage the solar panels over time. The chemistry of the water is not recommended for the solar panel’s glass.

 

My recommended cleaning products for solar panels

It is essential to clean the solar system using the correct cleaning equipment. Though the panel’s glass is strong, abrasive materials can scratch and damage the surface, thus reducing its performance or destroying the module.

Solar panels installed on the ground can be washed using a sponge or a very soft brush. For those located on the roof, a soft brush is advised, coupled with a long extension to reach the roof. This makes the work safe and easy, as it’s from the ground.

 

How to Clean Solar Panels (a Step-by-Step Guide)

Here’s a short guide on how to clean your solar panels in no time:

 

1. Shut down the solar system completely

The solar system should be shut down entirely before cleaning, as per the shutting down procedure written on the manufacturer’s manual. The DC systems should be shut down completely, while the AC system should be turned off using the main solar switch.

If possible, unhook your panels completely and place them somewhere where the wires will not get wet.

 

2. Brush off dust and any dirt

Start by brushing and removing dust and any loose debris that has settled on the panels’ surface before wetting them. This will make the process of cleaning easier and faster.

 

3. Wet the solar panels

After removing all dirt and dust, wet the panels by spraying them with your hose. If the panels are not very dirty, this should be enough to clean them. The water pressure should be regulated. Don’t use anything above 40bar, as this will get water into the junction box.

 

4. Tackle stubborn dirt and grime (gently)

If you get stubborn materials stuck to the surface of your panels, like bird droppings, gently use a soft cloth or windshield cleaner (with mild dish soap) to get rid of it.

 

5. Give your panels a final rinse

After, give your solar panels a final rinse by spraying them with clean water. Ensure that all soap, if used, is washed away completely.

 

6. Let the panels air dry

This will prevent streaks of water or soap (if you happen to leave some) from accumulating.

 

7. Hook your panels back up & turn them on

Hook up your panels once you have ensured that they have dried completely. Then, switch on the solar system at the inverter. Check to see whether everything is working properly.

 

How to Clean Around Your Solar Panels

It’s not uncommon for little things, such as leaves or twigs to get stuck under your panels. Here’s how to clean that:

 

How to clean leaves from under the solar panel

The best way to clean leaves from under a solar panel is by:

  1. Turning off your system completely.
  2. Then, taking off the panels.
  3. Tackling the mess gently (be careful not to disturb the wiring).

It is advisable to take your solar panels off your roof when cleaning for leaves. Failing to do so may be dangerous. The wiring of your panel is housed underneath, so when grabbing for leaves, you may pull a wire with it.

I don’t recommend it, but if you’re in a rush and don’t have time to take off the panels, the best way to clean the leaves from under their solar panels is by connecting a wet and dry vacuum to a PVC pipe and sucking them out.

 

How to clean snow from solar panels

Here are some methods used to clean snow from your solar panels:

 

1. Hose the snow

Spraying the solar panels is also another option, but be careful not to use hot water.

 

2. Brush off the snow

Brush off the snow with a soft cloth. Do not use a broom as this can damage the surface of the solar panels.

 

3. Heat the snow

Some people get creative and connect a leaf blower to long PVC pipes to blow the snow off the panels or generate warm air that will aid in melting the snow.

 

4. Wait for it to melt

If all else fails, merely waiting for the snow to melt can be the perfect solution. This method is great for people who have panels that are pitched at an angle of 35 degrees or more. Normally, the snow will melt and go away on its own. The steeper the panel installation, the faster the snow will slide off.

If your solar panels are on an RV or campervan, park your vehicle in the sun to speed up the process.

 

How to keep solar panels clean

Here are a few tips on keeping your panels clean, so that they can keep running efficiently:

  • You should do a visual inspection monthly to look for any buildup of dust and any dirt.
  • If you can’t do a deep clean, try scrubbing your panels with a light sponge or gentle cloth at least once a month or so.
  • If you reside in the western United States, where wildfires occur annually, you should inspect your soot and ash buildup panels after any major fires.
  • Monitor your bills or solar statements for any drop inefficiency. Changes can mean that the solar panels need cleaning.
  • If you live in a campervan, clean your panels after visiting a dusty location, such as the desert.
  • When the panels are installed, ensure that they are put in an angle that will favor self-cleaning for easy maintenance. I recommend installing them at a 35-degree angle or more. This makes it harder for debris, like leaves or twigs, to accumulate on top of the panels.
  • Hire a professional to do a deep clean if your panels are particularly dirty.

 

Final thoughts

Now that you are aware of how, when, and how often you will need to clean your solar panels, the final step is to actually go ahead and do it. Before washing, though, make sure to adhere to all the safety protocols put in place by your panel’s manufacturer.

It’ll help to read your solar product’s manual, which will provide you with more information on how to clean your panels effectively. Don’t let dirty panels bar you from experiencing the full power and potential of your solar panels.

If you liked this post or found it helpful, be sure to check out my favorite solar panels.

Victoria Miller

I'm the founder of NTT. I live in Miami, Florida, and enjoy learning everything there is to know about tiny spaces.