Guide on How to Clean Your Solar Panels

If you look up and notice your solar panels are buried under a layer of gunk, it’s time to clean them. You can’t just clean them with anything. You have to know how to clean your solar panels. 

You can’t count on the rain to remove the bird poop, pollen, dust, and leaves from your solar panels. When a solar panel is dirty, energy productivity slows down by up to 30%. A decrease in production increases your energy bill. 

It’s your job to make sure your solar panels stay clean so that their renewable energy output will continue saving you money.

Why You Need to Clean Your Solar Panels

Before you get started on the project of cleaning your solar panels, you may be wondering why you need to clean your solar panels in the first place. Is it even worth all the effort?

Dirty solar panels can underperform in producing solar power, so cleaning them boosts their energy efficiency. 

Some homeowners might assume that rain will keep solar panels clean. While this is true to some degree as rainwater rinses off loose debris, it won’t wash away all the gunk stubbornly stuck to the glass surface. On top of that, rain leaves behind water streaks that hinder the solar panels from absorbing sunlight. 

When your solar panels get too dirty and it’s a problem too big to be resolved by the rain, your solar panels need cleaning.

How Often Should You Clean Your Solar Panels?

Solar panels should be cleaned twice a year. In areas that receive a lot of rainfall, you may only have to clean your panels once a year.

How often solar panels need to be cleaned depends on how quickly the modules get dirty. Homeowners should do a cost-benefit analysis to determine if a solar panel cleaning is worth it, as studies show that solar panels can still perform well even after not having been cleaned for a while, and the monetary gain may not be large enough to cover the cost of solar panel cleaning service fees. 

Although other times, dirty solar panels can decrease energy output by 30% or more. 

Cleaning solar panels may not always be necessary and can be fairly infrequent – it largely depends on the area. External factors that call for your solar panels to be cleaned more frequently include:

• Dry, dusty environments. Hot climates with lots of dust or pollen in the air require more frequent cleanings. Arid or desert-like biomes are especially prone to large amounts of dust and dirt. 
• Bird droppings. If your solar panels are dirtied with bird droppings, they will need to be manually cleaned. Bird droppings cannot be washed away by the rain and they block the solar panels from absorbing sunlight. 
• Trees. Nature lovers enjoy a home with a beautiful greenbelt, but the nearby trees aren’t such great news for your solar energy system. Trees drop leaves, pollen, and sap, which is problematic if it gets on your panels.
• Smog, smoke, or air pollution. Pollutive particles in the area cloud the glass of a solar panel and decrease its effectiveness. In wildfire-prone areas, ash can be a problem if it lands on your roof. 

When to Clean Your Solar Panels

You can check your monitoring system via an app that tracks the performance of your solar panels’ energy output. If your solar panels are underperforming, it is likely a sign that they need to be cleaned to get them back to producing energy at max efficiency. 

Timing is key and that includes when to clean your solar panels. You want to pick the optimal time of year and time of day to clean them. 

Here are a few suggestions of best times to clean your solar panels:

• Spring or fall. Summers are often dry and dusty, so they aren’t the best season for cleaning solar panels. Avoid the summer heat and clean your panels when the weather is cooler.
• Cool days. A solar panel’s job is to absorb heat from the sun, so needless to say, a solar array gets very hot on hot days. Pick a day when the temperature is cool to clean your panels. If the panels are hot, the water will evaporate more quickly, which results in undesirable water stains. 
• Evenings or mornings. It’s best to either clean your solar panels first thing in the morning or late in the day. The afternoon sun heats up your panels.
• Overcast days. Avoid cleaning solar panels on bright, sunny days. Solar panels absorb a lot of heat from the sun overhead, and you don’t want your solar panels to be hot while you’re cleaning them.

Tools to Use for Cleaning Solar Panels

Before you learn how to clean your solar panels, you first need to know what cleaning products you need for the job. Here is a list of tools to help you during the solar panel cleaning process:

Soft-Bristled Brush

Always use a soft-bristled brush with a long handle that will allow you to clean the panels from the ground. Be careful not to scrub too hard or you might risk scratching the glass. 

If you don’t want to use a brush, you can also use a sponge or soft-bristled broom to wipe down your solar panels. Just make sure to use a soft sponge. Do not use any abrasive sponges like steel wool.

Cleaning Kit

If you don’t want to purchase a bunch of cleaning supplies separately, some companies sell solar panel cleaning kits. These kits are a pre-assembled collection of cleaning tools used for solar panel cleaning projects. They typically include tools such as:

• Biodegradable soap
• Cleaning cloth
• Extension pole
• Squeegee
• Soft-bristled brush
• Wiper

Cleaning Solutions

One of the best cleaning solutions to use is white vinegar. Don’t use cooking vinegar, as its high levels of acid are harmful for a solar panel. 

You can make a vinegar solution yourself by mixing these three ingredients together:

• ¼ cup white vinegar
• 2 cups deionized water
• ¼ teaspoon dish soap

You should avoid abrasive soaps or detergents. Mild soap such as dish soap is safe for solar panels, but many soaps and detergents tend to leave behind water stains. Not only do these water stains block solar modules from properly absorbing sunlight, they actually attract dirt and dust to the surface of the panels. 

Windex is a good cleaning product to use for cleaning solar panels, as it is cheap and easy to find.

Soft Cloth

A cleaning cloth can be used for both scrubbing and drying. Make sure to get a non-abrasive, soft cloth with a gentle material.

Hose

One of the most important tools for good solar panel cleaning is a water hose to rinse down your solar panels. 

If a simple rinse-off is all your panels need, then you can spray the panels from the ground with a garden hose. Otherwise, you will need a hose on hand to wash off the dirt before and after you scrub your solar technology clean. 

Leaf Blower

If your panel array is covered in dirt or leaves, you could use a leaf blower to blow off the debris. This is an effective method for getting rid of leaves. While it may not be as effective at getting rid of dirt like a thorough scrubbing would be, it will at least knock off some loose dirt. 

Squeegee

After you are finished scrubbing the panels, you can use a squeegee to wipe off excess water. Squeegees are helpful for drying off solar panels and they can be used to prevent water streaks. 

7 Steps to Manually Clean Your Solar Panels

If you are planning a DIY cleaning job, the first thing you need to do is gather your supplies. How thorough you want to be is up to you, but you will at least need either a hose or a bucket of water as well as a scrubbing utensil of some kind. 

Step 1: Turn Off the Solar Panels

Always remember, the very first thing you should always do when cleaning your solar panels is turn them off. It is essential that solar panels are powered off while they are being cleaned, otherwise the mixture of electricity and water could cause electrocution. 

Step 2: Rinse Your Panels

Rinse down your panels with lukewarm water to wash off loose dirt and debris. 

Step 3: Apply Cleaning Solutions

Spray the panels with a cleaning solution such as vinegar, Windex, or soapy water. If you are cleaning from the edge of a ladder, you can manually spray the panels with a spray bottle. Otherwise, you should be able to scrub down the panels with a long-poled brush. 

Step 4: Scrub Down Panels

Scrub the panels with a soft brush to remove any dirt, debris, or stains on your panels. To scrub your solar panel system, use a long-handled brush to reach the solar panels from the ground. 

Step 5: Rinse the Panels Again

Once you’ve finished scrubbing, rinse the panels again with lukewarm water.

Step 6: Dry the Panels

After the washing is done, you can finish up by drying down the panels. A soft drying cloth or squeegee is best for removing excess water. While it is easier to let panels dry off naturally, drying them off manually will prevent them from forming water stains, which slow down solar panel efficiency.

Step 7: Clean the Solar Inverter

In addition to cleaning your solar panels, you should make sure that the solar inverter stays clean too.

The solar inverter is one of the most important components of a solar array, as it is the device that transforms sunlight into usable energy. If dust infiltrates a solar inverter, it can cause system failure and lead to the inverter stopping to work altogether. 

Solar inverters are stored outdoors where they get dirty quickly. To help them stay clean, every so often you should wipe them down with a cleaning cloth.

Automated Solar Panel Cleaning

If you don’t want to clean your solar panels yourself or deal with hiring a solar panel cleaning company, there are technological automated cleaning systems that clean your solar panels for you. 

Automatic Cleaning System

Automatic cleaning systems are self-cleaning machinery that automatically spray down solar panels with water and use specialized brushes to wipe off the grime.

You can use this robotic technology to schedule regular cleanings. The advantage of automatic cleaning robots is that once installed on the roof, they are self-cleaning and require no human labor. 

The problem is that automated cleaning robots are expensive, as the technology is fairly new. 

Automatic Cleaning Robot

Automatic cleaning robots are a similar self-cleaning technology. These robots run on solar panels and give your solar panels a daily cleaning. What’s even better is that automatic cleaning robots don’t use water to clean, making them more eco-friendly. 

Unfortunately, the technology is expensive, with prices usually ranging around $3,000. These solar panel cleaning robots are popular in dry climates where there is a lot of dust and dirt. 

How to Clean Snow Off Solar Panels

While snow is pretty to look at and opens the door to fun activities such as sledding, ice skating, and snowman-making, it also smothers your solar panels under a blanket of snow, preventing PV cells from absorbing sunlight and generating solar power. 

If you want your solar panels to produce solar energy while there is snow outside, you will have to remove the snow from the solar panels. Here are some quick tips on how to do that:

• Use a soft-bristled broom. To remove snow, you shouldn’t use a shovel or any other abrasive tool that might scratch or scrape the glass surface. A soft-bristled broom will protect the surface of the solar panel while removing snow from the panels. 
• Use a snow rake. There are snow rakes specially designed for solar panels. 
• Don’t use hot water. Extreme temperature change from frozen to burning hot will crack the glass.
• Use a long-handled broom. You don’t want to climb on your roof while it’s snowy outside, since it’s hard to secure a ladder when the conditions are icy and slippery.
• Use a snowblower. If you have a snowblower on hand, you can use that to blow off snow from your panels. 

When you are cleaning snow off of your panels, you should stand a little ways back from the edge of your roof, as knocking snow down will cause a mini avalanche off of your roof. You don’t want to get caught under the cascading snowfall.

Tilted solar panels shed snow easier, so if you live in a snowy area, you should make sure that your solar panels are set at a slight angle during the winter.

Dos and Don’ts of Cleaning Solar Panels

Before you get started cleaning your solar array, there are some tips and tricks you should know to make the job a breeze and make sure you take the appropriate safety precautions. 

DO

When you are cleaning your solar panels, here are some things you should always do: 

• Turn off solar panels. Always do this step first, before anything else. 
• Work from the ground. Don’t climb up on your roof if you don’t have to. Long-handled brushes are available so you can reach the panels from the ground, or at least from the edge of the ladder. 
• Clean during the cool hours of day. Solar panels are harder to properly clean when they are warmed up because water evaporates more quickly on a hot surface, which risks leaving behind water stains. Aim to clean your solar panels during mornings, evenings, or cloudy days. 
• Dry off the panels. Water stains block panels from absorbing sunlight, so after you clean them, dry off all the moisture to avoid leaving behind water spots.

DON’T

There are some pitfalls you should avoid when cleaning solar panels, so to avoid making beginner’s mistakes, don’t:

• Use a pressure washer. Unless you want to wreak havoc on your solar panel system, you should never use high-pressure jets of water. The water pressure of a focused blast can cause the panel to crack. 
• Use cold water. Sunlight charges photovoltaic solar cells, which heats up the system. Cold water on warm panels creates an extreme temperature difference, which cracks the glass. Instead, use lukewarm water to clean them.
• Use hard water. To clean a solar panel, use calcium-free or distilled water that is free of minerals. Hard water is full of minerals that leave behind white residue and result in water stains. 

Benefits of Cleaning Your Solar Panels

You may be wondering if there is any point to going through the effort of cleaning your solar panels. After all, if you are going to clean your solar panels, you want to know what the advantages of such an undertaking are.

There are many benefits to cleaning your solar panels:

• Energy efficiency. Cleaning your solar panels will increase energy output by about 10% to 30%. 
• Increases curb appeal. Dirty solar panels are not pleasant to look at. To keep the sleek, modern look of your panels intact, clean your panels at regular intervals.
• Provides an opportunity to inspect panels and roof. Cleaning your PV system gives you or a professional cleaner the chance to look over the panels and inspect them to see if they need any repairs. 
• Improves ROI time. Solar panels cost a lot, so you want your solar panel purchase to pay itself off as quickly as possible. The faster the energy production rate, the more quickly it will pay itself off in the end, and the sooner it will start saving you money on electricity bills. 
• Keeps your warranty. Some solar panel warranties require that homeowners clean the solar panels regularly. Failure to keep with regular cleanings may result in solar companies not honoring the warranty agreement in regards to solar panel maintenance. 
• Increases lifespan. A cleaner solar panel is more durable and lasts longer. 
• Prevents hot spots. Too much dirt on a solar panel can cause part of a module to overheat, which is known as a hot spot. Ultimately, keeping PV cells clean is safer for your solar panel. 

What Makes Solar Panels Dirty?

Any object left outside will inevitably get dirty due to exposure from the outdoor elements. However, there are things that can be done to minimize these external factors soiling your roof. 

To prevent your roof from getting dirty, a good place to start is to understand what different factors are typically responsible for soiling solar panels:

• Air pollution
• Algae
• Ash
• Dirt
• Dust
• Bird droppings
• Foliage
• Leaves
• Pollen
• Salt
• Sand
• Sap
• Smog
• Smoke
• Water stains

To avoid leaves and sap from cluttering your solar panels, make sure to keep tree branches trimmed away from your roof. This isn’t only a good idea for protecting your solar panels, it’s also a good way to protect your roof and to make sure that your solar panels aren’t too shaded and receive enough sunlight.

You may not be able to stop birds flying overhead from using your solar panels as a bathroom, but you can prevent birds from nesting around your solar panels. To keep birds away from your solar array, you can install spikes, plastic predators, or install mesh wire to block off openings under your solar panels.

DIY or Hire a Professional to Clean Solar Panels?

It’s important to keep your solar panels clean, but should you clean them yourselves or hire a professional?

There are many benefits to hiring a professional solar panel cleaner:

• You don’t have to take risks of climbing up on a ladder. If you don’t have the physical ability to clean a roof or are simply not comfortable with cleaning solar panels yourself, then it is beneficial to hire a pro.
• Pros already have all the equipment they need. If you hire a professional cleaner, you won’t need to buy any tools yourself, as solar panel cleaners come equipped with all the supplies needed for a solar panel cleaning job. 
• It saves you time. Cleaning solar panels takes time, and that may be time you don’t have. If your schedule is full, you can save yourself the time with professional solar panel cleaning services. 
• Pros can inspect your solar panels A professional solar panel cleaner knows what to look for when inspecting your solar panels. While they are cleaning solar panels, they can also check your panels for damage and let you know if your solar array needs repairs. 
• You don’t risk making mistakes. If you are inexperienced with cleaning solar panels, beginner’s mistakes can result in damaging the solar panels.

The benefit of a DIY job is that you don’t have to pay service fees, as the cost of solar panel cleaning typically ranges from $5 to $35 per solar panel. 

If you decide to do it yourself, just make sure to gather all the equipment and tools you need and don’t take the unnecessary risk of climbing up on your roof. 

FAQ About How to Clean Solar Panels

How to Boost Solar Power Performance

Clean solar panels have much better efficiency and durability than dirty solar panels. If your solar panels have been underperforming lately and you’re ready to get their energy output back on track, then it’s time to clean your solar array. 

If you want professional solar panel cleaning, find a solar panel cleaning company in your area today. 

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