Does Cleaning Solar Panels Make a Difference?

Solar panels are made to be exposed to the elements. However, this does not mean that they do not require any maintenance. Although very little and only from time to time, a good cleaning routine can help your solar energy system generate more – energy. In fact, clean panels are known to produce more power, while leaving them dirty for too long can risk making them more susceptible to breakage and malfunction. 

However, cleaning them too often or too aggressively can cause other types of issues, which again include breakage and malfunction. For this reason, you should either: 1. Hire a professional, or 2. Learn how to do it yourself. As the first option can be costly, we will focus on knowing how to clean them yourself. Cleaning solar panels does not take much time, can be done in an afternoon, and you will be rewarded with a higher solar power production without hiring a costly solar panel cleaning service. 

We will also discuss some affordable cleaning tools and compare them. Knowing what types of tools you should use is one of the best ways to prevent scratches and other damage to the (not so) delicate solar panels. Knowing what each tool can remove will keep dirty solar panels at bay and will help the panels installed on your rooftop offset as much of your energy consumption as possible. With that being said, let’s move on and dive right in. 

Solar Energy Equipment Maintenance

So, cleaning is important. But what parts to clean and what parts to avoid? After all, shouldn’t you clean the entire system at once? Well, not really, as this can cause more damage than good. Your solar panel system is a complex system, consisting of many parts: 

• The solar panel array, 
• The wiring, 
• The solar inverter, 
• The solar battery, 
• The solar charge controller, and 
• The connection to the main panel. 

The solar panel array further consists of all the solar panels you have that are connected to the system. This is the only part of the system that you should clean. This is the part that produces solar power and should be kept as clean as possible to maximize the solar output of your solar panels. 

The wiring on the underside of the panels should never be touched. These are ‘live’ wires, and you risk either damaging them or getting electrocuted. The only time you should really check the wiring is if you notice birds underneath (in systems with a wider gap between the roof and the panels) or if a particularly strong wind log in a branch in the space between. In all other cases, this is a job of a professional to check. 

All other parts, including the solar inverter, the solar battery, the charge controller, and the connection to the mains, should never be touched. Making sure that these parts of the solar panel system are kept dry and protected from the elements (such as your garage or a special shed), should be enough. Keep the area around them clean and easily accessible (no boxes with old toys around them), and you will be good to go for over a decade. 

Never forget that all parts of your solar panels and all other equipment should be inspected once a year. This should pinpoint any problems that your system may encounter and will help you get the most out of your solar panels. Solar panel cleaning services should be called in for regular maintenance, but a lot of the work is the work you can do yourself. 

Cleaning Solar Panels

This work generally includes removing any debris and dust that may have settled on your panes. The debris can include leaves of all sizes, shapes, and colors, pollen particles, bird droppings, and all other debris that is specific to your area. On the other hand, some dust is present wherever you live, so it should be cleaned regularly, irrelevant of where you may live. 

As always, the location where the solar panels are installed is not the only thing that can influence your solar panels efficiency and how often you should clean them. In fact, there is a number of factors that you should consider in addition to giving them an eye inspection every week or so: 

• The area you live in, 
• The vicinity of any agricultural fields, 
• The vicinity of thermal power plants (especially coal and oil-powered), 
• The vicinity of blooming trees and other vegetation which may produce a lot of pollen, 
• The vicinity of large bodies of water, especially the sea and the ocean, 
• The orientation and tilt (the angle) of your solar panels, 
• The vicinity of desserts, 
• Nearby bird settlements, and migratory bird patterns
• The precipitation patterns in your area. 

All of these should be taken into account, as all of these factors may contribute to making your solar panel maintenance more or less frequent. DIY solar panel upkeep is not difficult, but doing it too rarely can compromise the panel efficiency while doing it too often and in a less-than-ideal way can compromise their structure, increase the corrosion rate, and, overall, damage your solar panels. You do not need entire solar farms to pay attention to all these details – a few minutes of your time spent researching the topic is usually enough.  

Common Causes of Dirt in Solar Panels

With all these factors influencing your solar panel’s performance, the story should be made simpler before we make it detailed again. Regular cleaning is necessary, especially for all those who want to rely on renewable energy output for most of their energy needs. Knowing how and when to clean your panels will provide you with maximum efficiency and will influence which cleaning tools you use: in most cases, a soft sponge and a very mild dish soap will resolve 99% of the issues that may interfere with energy production. 

Dust, leaves, water, bird droppings, and pollen are among the most common polluters that can influence your system’s efficiency. Regularly cleaning these will make sure your panel work at peak capacity and that your solar investment is paid back in as short of a time as possible. Now, let’s consider different pollutants that may stick to the glass surface, rendering solar cells useless. 

Dust

The first and the most common polluter is dust. The dust consists of hair, dead skin cells, small fragments of plastic and sand, or even soil – depending on where you live. This does not mean that living in an area with a lot of trees and little to no exposed soil nearby will guarantee that you will have no issues with solar panels – remember that there is some dust even in rainwater and that clean solar panels mean no residue on them whatsoever. 

The dust issue is especially pronounced in desert areas, as well as in agricultural areas. In the former, dust is an ever-present problem, especially if you live down the wind from sand and areas with eroded land – more frequent cleaning resolves this issue. However, if you live in an agricultural area, your panels may get covered in dust every time the land is tilled – especially during spring and autumn, and even in the summer in multi-crop or multi-harvest areas (generally to the South of the US). 

Leaves

Dust is almost never an issue in heavily wooded areas, as trees help clean the air and filter out all the soil and sand particles from the air, especially when coupled with regular rainfall. However, these trees could be deciduous, and the leaves that fall from them every autumn can get carried by the wind for miles at times. These leaves can then be deposited onto your solar panels and cover a larger area in a single day than dust ever could. 

Leaves can be removed by means of a soft brush or a water hose. However, leaving them on the panels for too long can cause issues, such as partial breakdown, where the leafy materials turn into a paste of a sort that sticks to the panels and may require more scrubbing than blowing them away. In any case, if you need regular gutter cleaning, you will need regular panel cleaning as well. This is usually done once a year, in late autumn when most leaves have fallen. 

Water

We’ve already mentioned that you can use water to remove the leafy deposits and dust from the solar panels, but did you know that water can also make your panels dirty? The thing is that all water, rainwater included, contains minerals and impurities that most homeowners would not stress about too much. However, these impurities and minerals can solidify over dirt deposits and debris that already exist on your solar panels, making them mat and stick to the surface of the panels. 

In this case, professional cleaning services should come to the rescue and restore the solar panel’s performance. The thing is that cleaning these solidified deposits requires one to climb the roof to remove them by hand or by tools, and not everyone has the necessary safety precautions and equipment to do that safely. However, regular hosing down or brushing down of your panels should help tremendously and prevent you from having to call professional services to keep the panels in their top shape. 

Bird Droppings

Besides water, another kind of liquid is notoriously difficult to remove from the panels. These would be bird droppings. These droppings are the most common in areas where there are a lot of birds, in areas over which birds migrate twice a year (both in the spring and the autumn), and in the vicinity of bird sanctuaries. 

Bird droppings are a notorious enemy of your solar system, as they can deliver multiple types of damage all at once. They cover the panels, making them less efficient. They can damage the protective lining on the exposed metal parts of the panels (thanks to harsh chemicals that can be found in bird droppings), causing corrosion and possible water penetration. In addition to this, some smaller birds may decide to nest under your panels, possibly causing damage to the wiring. In any case, birds are a big no no for your panels. 

Pollen

And finally, pollen is another pollutant that can be frequently found on solar panels. This type of pollutant cannot be removed by water only, as in most cases, pollen is either fatty or water-repellent. Frequent cleaning with a brush and water seems to do the trick, but be careful not to damage the protective lining on your solar panels. A soft cloth and some mild laundry detergents can help clean the panels, but make sure to be cautious and always rinse the panels after using soap. 

More frequent cleaning of your panels will help prevent a lot of damage done to them and will help you achieve all the positive effects of new (and clean solar panels). Regularly removing dust, pollen, bird droppings, and leaves will also protect your panels over longer periods of time, as dirty areas produce no electricity, can overheat, and even burn out. When you clean your solar panels regularly, you ensure the maximum of each solar panel’s performance, fewer visits to solar companies, and less money spent on professional cleaning companies. 

Effects of Cleaning Solar Panels

So, an increase in the production rate of your panels is one of the most common benefits that you can see when you keep your panes clean. Professional cleaners charge a lot, so investing in a simple soft brush and some cleaning tools with low cleaning power (pressure washers are out of the question) will help you tremendously. 

Solar panels that are kept clean can produce at least 5% more power than those that are not kept clean. In fact, your panels can lose up to 5% of their efficiency per quarter, a trend that continues until the panel loses about ⅓ of their total power output – or about 35% of it. That can all add up to up to 20% power output loss every year, so make sure there is no bird poop and leaves on your panels. 

Besides an increase in power production, extra cleaning will also help your panels last for much longer. Panels that are dirty, even partially, will overheat, especially the solar cells that are covered in dirt. This can make them burn out and last less than your warranty says, they should – typically 20-30 years. A buildup of dirt not only damages their production and longevity but will also attract birds and pests. 

Solar Panel Cleaning Options

To keep all this damage at bay, it is important to clean your solar panels at least (!) once a year. This will keep them in their pristine state and will guarantee that you get exactly what you paid for – a lot of solar power and less build-up of pollutants. As a rule of thumb, whenever you think you should clean your gutters, clean your panels as well. 

DIY Solar Panel Cleaning

So, assuming you clean the gutters once a year and in the fall, this is the perfect time to clean your solar panels. In a DIY setting, you will need a water hose, a brush (a soft one), and a soft rag. You may also want to use soapy water, especially in areas prone to pollen and bird droppings. 

Start by hosing down the panels with water, but avoid getting water splashes on the underside. You should also consider doing so early in the morning or an hour or so after the sun has set to prevent cracks from cold water hitting the hot panel surface. Wearing a safety harness is also a must, even with a lot-lying roof, as you can never be too cautious. 

Once this is done, you should use the brush or the rag to remove any dirt that may have stuck to the panel’s surface. Doing so will render the solar panels clean, even from the dirt and oily stains that you may not always be able to see. This will improve the solar panel’s performance. Once done, you should use the garden hose again to remove the soap residue and any particles that got loose while scrubbing. 

Safety Tips

At all times, you should keep caution and wear your harness. This will guarantee that you do not slip and fall. Never forget that the roof is tilted and that soapy water can get very slippery, irrelevant to the surface, or drops on. Always wear protective boots and never step on the panels themselves – they can be very slippery, causing you to fall, and may even crack under your own weight. 

Professional Solar Cleaners,

On the other hand, you can always call professional cleaning services. They will come, estimate the dirt build-up and the type of dirt, and will be able to use professional (and gentle) solar panel cleaning tools that you may not have or not know how to use properly. You will have to pay, though, depending on the size of the system, the ease of accessibility, and the dirt built up 

When do you Call for Cleaning?

You should not call cleaning services every time you clean your panels. In general, once a year will suffice, especially if you have a lot of pollen in your area or bird poop on the panels themselves. Dust buildup can be removed more easily, and you will be able to take care of that yourself. Mind you, waiting for the rainfall to remove the dirt will not rid you of all of it – in fact, experiments show that actually cleaning your panels will provide you with more power output than rainfall ever could. 

Automated Solar Panel Cleaners

As an attempt to reduce cleaning costs, especially with dust build up on solar farms, automated solar panel cleaners clean instead of you or the workers with a soft cloth. These cleaners are automated, can be very gentle to the surface of the panels, and use a mix of brushes and water to remove most of the dirt. There are even software solutions that can monitor the power output of your solar panels and inform you when it may be time to clean them. Some cleaning professionals use these solutions. 

Solar Panel Cleaning Costs

Since there are many ways to clean your solar panels, it is worth comparing their pricing. We’ve mentioned DIY cleaning, calling professionals for help, and using automatic cleaners. Let’s consider the pricing: 

How Frequently Should You Clean Solar Panels?

The solar industry standard for when solar panels need cleaning differs from state to state and area to area. However, they should be cleaned AT LEAST once a year. However, there are some factors that you should consider that may say you need to clean your panels more frequently. These include: 

• The location of solar panels, 
• System design, 
• Installation angle, 
• Size of solar panels, 
• The number of solar panels, 
• The types of dirt commonly found in your area, and 
• The local weather. 

Location

The location is the sole most important contributor to how often you should clean your solar panels. The location will influence by specific pollutants, pollen, bird migratory and settlement patterns, the vicinity of water bodies, and eroded soil areas (deserts). Let’s check them out in more detail: 

Polluted Areas

Polluted areas are any areas where there are factories, thermal power plants, highways, airports, etc. These areas are known for increased dust and micro and nano plastic particles and their concentrations. In addition to these, your solar panels may also experience a higher build-up of oil stains, which can lock in all other types of pollutants and render cleaning with water only impossible. 

Wooded Areas

Heavily wooded areas have the benefit of filtering the air as it passes through them to remove or reduce other types of pollutants, in particular dust and any particles. However, wooded areas are also prone to producing more pollen, which can stick to the surface of your solar panel. The solar industry also notes that areas with a lot of deciduous trees pose the issue of fallen leaves covering your panels. 

Deserts

Deserts and any areas with eroded or eroding soil can also pose significant issues to solar panels. These areas are known for high dust concentrations and the heavy buildup on the panels themselves. In these areas, solar panels need cleaning more often than once a year. A single sand or dust storm can easily reduce the efficiency of your panels by up to 35% – meaning you should clean them every time there is a storm. 

System design

The way that your system has been designed can also influence how often you should clean your panels. All the pollutants reducing efficiency can be removed or made difficult to stick to your panels by means of microstructure on the panel surface, removed by means of waterless vibration or the installation range. 

Installation Angle

The installation angle here is unfortunately fixed and is usually tied to the number of degrees of latitude. This means that if you live at 45 degrees North, this is exactly the tilt that your panels should have. A higher tilt means that more dust will be blown away or washed away naturally, rendering cleaning your panels much less frequent. However, the closer to flat panels that you get, the more difficult it gets to clean them and the more deposits there will be. 

Size/number of Panels

The size of the solar panels can make them more prone to certain pollutants, such as dust, as smaller panels mean smaller vertices can form and clean them for you. Likewise, the more solar panels you have, the less frequently you will need to clean them, as more panels should be able to produce more power than you really need – up to 10% in some system configurations. 

Types of dirt

The type of dirt deposited on panels can also have a say in how often your should clean them. Not all types of dirt reduce the light that passes through this dirty layer equally. In general, the bigger the particles, the worse, and the same go for the color of the particles themselves – the darker they are (exhaust from cars, planes, or factories), the more light they will absorb, making you clean your solar panels more frequently. 

Weather

The weather patterns can help and do the cleaning for you. Namely, each event of rain will remove some dirt from your panels. If you experience rain every few days or even biweekly, you will need to clean your panels only once a year. On the other hand, in areas with heavy snowfall, you will need to clean your panels more frequently – this time, to remove snow. 

The duration between Thorough Cleanings

There is no ideal time or duration between the cleaning sessions of your panels. In fact, you need to observe them to make sure they can stay reasonably clean. In general, cleaning them once a year is a must, while anything more frequent than this should only be done if there is a need for it. Desert areas and agricultural areas are also areas where panels should be cleaned more regularly. 

FAQs

Conclusion

Your panels need to be cleaned only once every so often. And while once a year is the gold standard, cleaning them even more frequently with a non-abrasive sponge should be done in some areas. Keeping your panels clean will help you increase their power output and will help them pay off faster. 

Updated on 06-14-23