Pressure Washing Solar Panels
Generally, solar panels require little maintenance to function properly. You only need to clean them periodically to get rid of dirt, grime, leaves, and other debris that accumulate over time. If you decide to clean the panels yourself, a pressure washer could be the first thing that comes to mind. But how safe is it?
While pressure washers are excellent for cleaning your home’s exterior, such as the roof, gutters, siding, and walkways, they should never be used to clean solar panels. This is because solar panels are not designed to withstand high pressure, and using pressure washers risks damaging them.
In this article, we will educate you on the proper ways to clean your panels and what you should avoid.
What happens when you pressure wash your solar panels?
Pressure washers may seem to be the faster and easier way to clean solar panels, but they are not recommended because the high pressure can damage the panels.
Here is what can happen if you clean your solar panels with a pressure washer.
Damage the panel’s coating
Solar panels have a protective coating that protects the metal frame from harsh conditions. The intense pressure from pressure washers may damage this coating.
Over time, the coating may start separating from the glass panes of your panels, exposing them to harsh environmental conditions. This can cause irreversible rust and corrosion that may decrease the efficiency and value of your solar panels.
Void your warranty
Most solar panel manufacturers offer extended warranties for their panels and advise against using pressure washers to clean solar panels. So, if you clean your panels with a pressure washer or any harsh chemicals that can damage them, the manufacturer may decide not to honour the warranty and declare it void.
Overspray from pressure washing your solar panels can cause problems with your roof over time. If the water is not aligned properly, it can run below the roof and damage the outer coating of your tile, composite, or clay roofing.
How to clean solar panels: 5 tried and tested methods
There are several recommended ways to clean solar panels, including manual cleaning and using automated methods. While rainwater can do most of the cleaning for you, it is not sufficient to remove all the dirt, grime, and debris that accumulate at the bottom of the solar panels.
Below are 5 efficient ways to clean your solar panels.
Robotic technology has made solar panel cleaning safer and easier for many solar companies and homeowners. Portable automatic and semi-automatic robots can be installed on commercial and residential properties. The robots make solar panel cleaning easy and fast, and they are especially important for panels installed in dusty environments that require regular cleaning.
Brushes and sponges
Besides robotics technology, many solar panel cleaning and maintenance companies, such as US-based Bland Company and Premier Solar Cleaning, have found out that deionized water works perfectly for cleaning solar panels.
These companies use deionized water with a vehicle-mounted or rolling brush to clean the panels. No soap is used because it can leave streaks and smears that obstruct the panels from receiving maximum sun rays. Soap residues also attract more dust.
Polywater, a lubricant manufacturer, has produced a Solar Panel Wash that can help water remove grime without leaving streaks or films behind. Some companies use a mixture of diluted vinegar and hydrogen peroxide to clean solar panels.
Homeowners can also clean their panels with a soft sponge and a garden hose without any cleaning agents.
Cleaning Your Solar Panels
If you have a residential solar energy system installed, your solar panels are generally flat, tilted, and on your rooftop. How often do you clean your roof? Probably not very often, most likely never. Why’s that? I hear you saying “Isn’t that what rain is for?” That’s kind of the same logic for solar panels too.
In most cases, you won’t need to clean your solar panels often, if at all. After all, anything that accumulates dirt on them (for example, dust or pollen), will get washed off the next time it rains. There are some times it might make sense to clean your solar panels though. If you’ve got a lot of bird droppings on your panels, rain might not wash these off very readily, so it’s a good idea to clean them off. Also, if you live in a state that’s prone to droughts – or, if it rains, it’s only a very light, misty rain, you might need to clean them every now and then.
Do dirt and debris have an impact on the effectiveness of your solar panels? And if so, how much? Well, yes and no. And, not much. Yes, dirt and debris can affect how much sunlight gets through to convert the light to energy. But, the amount the efficiency is lowered is minute – maybe 5% or less. And, with a typical 5kW solar system, this might equate to about 20 of loss in your energy bill. Not monthly – overall. And generally, even if we are talking about areas with drought, eventually when it does rain, a couple months down the line, everything will be washed away and it might not even be worth it to deal with the hassle of cleaning it in the first place.
How to Clean Solar Panels
If you do decide your solar panels need to be cleaned, there are two main ways of doing it: hire a professional or do it yourself. A lot of solar companies will offer this type of service to you, for a fee of course. They might offer it as part of an annual maintenance service, or suggest you get it done every so often when they come to install the product. The truth is, what you get back cost-wise in your energy bill does not exceed the amount you need to shell out to these companies to perform the work. Solar companies often charge a steep amount to do this cleaning, for not much return on your energy bill.
On the other hand, if you were interested in doing it yourself, you’ll generally have all you need to do it at home. In most instances, it will involve nothing more than a hose, maybe some soap, and you’re good to go. This might be helpful in drought-prone areas as well, because essentially what you’re doing with the hose is the same thing the rain would do if you got more of it in your area.
There are ways to determine if your solar panels need cleaning to begin with. One is physical inspection of the panels for debris, dirt, bird droppings, etc. The other way is the use of a monitoring system that alerts you to how well your solar panels are functioning and performing. This can alert you to any maintenance needs for your system, whether that’s mechanical, electrical, or cleanliness.
What Do You Use to Clean Solar Panels?
If you are interested in cleaning your residential solar panels on your own, there are a variety of products you can use to clean them. But first things first. Check with your solar installers and providers to determine if there is any information about solar panel cleaning, recommendations, and dos or don’ts when it comes to cleaning your system.
The most effective way to clean your solar panels is with a hose and a bucket of soapy water. Essentially, in the same manner you would wash your car at home. Because you don’t want to scratch the panels in any way, it’s best to use just water and a non-abrasive sponge to apply soapy water. Keep in mind that you shouldn’t use any type of high-pressure water sprayer when washing off your solar panels. A high-pressure attachment can damage the solar panels themselves.
If you do use something other than just water – especially to get rid of pesky bird droppings, just make sure what you’re using is soft and hard bristle-free. Sponges are great products to clean solar panels with because they won’t scratch. If deciding to use a little bit of soap on your sponge, use something that you might clean your dishes with. Laundry detergents and other stronger chemicals might interact with your solar panels in a negative way. Remember that plain water works the best in 99% of cases.
Keep in mind that solar panels can be extremely hot when the sun is beating down on them. It’s best to pick a cool, overcast day to clean the panels. Not only to protect yourself from burns, but if you’re attempting to clean the solar panels when it’s extremely hot out, the soapy water you are putting on the panels will evaporate quickly and may leave a residue or smear to the panels which can affect their effectiveness.
Is It Worth It To Clean Your Solar Panels?
Based on the research, experts are leaning toward “no.” And especially if you want to hire a professional company to clean them over the DIY method. The return on investment is just not there to justify the trouble. Let’s take a look at some numbers. On average, when your solar panels get dirty, expect a 5% or less change in output. And that’s just when they’re dirty. In most climates, if there is dust or debris on the panels and their energy output is registered 5% less than other times, the next rain will wash away the debris and the solar panels will return to their optimal efficiency. Even if you live in a drought-prone area – it will rain again.
In addition, most solar panels are tilted to a high enough degree that most buildup will run right off the panel instead of sticking to the top of it. Even with tilted panels, you might have some slight buildup on the lowest panel (because the runoff collects at the bottom) – but the decrease in output based on this alone is so minuscule, it’s not something worth worrying about.
Lastly, it’s a pretty small tradeoff, energy-wise and cost-wise, to climb up on a ladder, get on your roof, and clean your solar panels yourselves. When you think about getting out there and dragging a hose up to the roof to clean them, this point might really start to hit home.
Maintenance and Upkeep
So, in general, let the rain take care of your solar panel cleaning. Monitor your system’s functionality by paying attention to your energy bills and usage month-to-month. If you start to notice changes in your electric bill, maybe it’s time to think about cleaning or some other type of maintenance. If you think fluctuations in your energy bill could be because you need solar panel cleaning, see if the efficiency returns to normal after a good rain. If so, that’s probably the end of it. If you find the functionality is still acting wonky, it might be something electrical that needs fixing instead of just cleaning.
When it comes down to solar panel cleaning though, a visual inspection, a rainwater bath, and you staying on the ground (instead of climbing up a ladder), may be all the solar doctor needs to order.
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Photovoltaic Cleaning Kit MTM Aluminum Lance
The dirt and residues present on the photovoltaic panels can lead to large losses in the efficiency of the system, so it is important to regularly clean it. The proposed kit is ideal for those wishing to use their own pressure washer to clean solar, photovoltaic or glass systems.
- 4.7 or 6.4 m telescopic lance
- Hydrokinetic rotating brush of your choice
- 1 liter of solar panel cleaner
Telescopic Lance MTM Hydro
Aluminum telescopic lance for pressure washer, with a length of 4.7 or 6.4 m selectable from the drop-down menu.
The lance is equipped with a gun and a high-pressure hose and is ideal for easily reaching the less accessible points when cleaning photovoltaic or glass systems.
- Nominal pressure: 25 MPa. 250 bar
- Admissible pressure: 28 MPa. 280 bar
- Nominal flow: 40 L / min
- Nominal temperature: 120 ° C
- Entry: 3/8 NPT F.
- Outlet: 1/4 NPT F.
- Closed lance length: 2 ÷ 2.5 m
- Weight: 5.5 ÷ 6.7 kg
Hydrokinetic Rotating Brush
Hydrokinetic brush with double counter-rotating brush, usable with high-pressure cleaners with operating pressure from 30 to 80 bar.
Equipped with nylon bristles and with a working pitch of 40 cm, this brush is ideal for cleaning particularly dirty panels and can also be used for cleaning Windows.
Floating Rotating Brush
Hydrokinetic brush with double counter-rotating brush system applicable for use with high pressure systems. The attachment with movable joint guarantees great flexibility during cleaning.
Total 40 cm working pitch and nylon bristles, ideal for very dirty photovoltaic modules.
Dianos FV Cleaner detergent
The FV Cleaner cleaner is a solar panel cleaner with antistatic properties that help prevent the formation of scale on the surfaces.
Thanks to its formula, it guarantees a high cleaning power on all photovoltaic panels, leaving the surface without halos or streaks and without attacking the frame of the panels.
To be diluted with water, the detergent can be sprinkled by hand, with a pressure washer or with machines for washing photovoltaic panels.
Comet ETM 150 XProfessional Compact Pressure Washer
4.5 from 108 reviews check by yourself
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What Homeowners Should Know About Solar Panel Cleaning
The appearance of any unknown substance on your solar panels can be a cause for concern. One of our customers recently contacted us about a dusting of white powder they saw on their panels. Our examination revealed that the culprit was pollen that had accumulated on the solar panels, so there was no reason to panic, as the panels were still producing energy, they just needed a good cleaning.
We suggested that they could start by spraying the pollen off using a water hose to clean the panels. Then we recommended that they sign up for a thorough panel cleaning service at least once per year. It would prevent build-up in the future and ensure maximum efficiency and savings from their solar power system.
This homeowner’s concerns got us thinking about the sort of solar panel cleaning questions that most homeowners have:
- Do solar panels need cleaning?
- What solar power cleaning tasks can you do on your own?
- When should you hire a professional cleaning company to clean your solar panels?
- Will cleaning your solar panels improve their performance?
This article will answer all your concerns regarding these and other questions.
What are the Causes of Dirty Solar Panels?
You need to oil, maintain, and clean your car so it runs more efficiently. Others want their house Windows to be crystal-clear and grime-free so they can enjoy the view of their property. For many of the same reasons, your solar panels also need cleaning. Accumulated leaves, bird droppings, and other debris can block a significant amount of the sun’s rays, reducing your system’s efficiency.
We all love trees, as they beautify and freshen up our property. But birds also love them for nesting or chilling spots. If branches hang over your solar panel array, you should be prepared to do some extra cleaning.
Bird droppings tend to be more notorious than dust, leaves, and pollen, especially if they harden and stick on the panels. The accumulated debris from birds can block significant light from the sun, and it’s more difficult to remove just by spraying your panels with water.
Thankfully, products and services exist that can indicate if bird droppings affect the current flow in your solar energy system. Microinverters help with this, as the technology allows you to see when a single panel is generating less electricity because of blockage or debris.
Pollen and Leaves
Pollen has evolved into a sticky material that doesn’t dissolve in water. As a result, it can be harder to clean since it doesn’t just blow away in the wind. If you live near farmlands or areas with a lot of vegitation, expect pollination agents like wind, insects, and birds carrying pollen to pass over your panels and drop some of it on them. In fact, windy weather is more likely to blow pollen onto your panels in the first place instead of blowing it away.
You may also need to deal with leaves falling on your panels, especially if your trees are deciduous, meaning they lose their leaves each year in the fall. While dry leaves just blow away in the wind, wet leaves typically stick to panels as heavy rain can act like glue.
Dust and Dirt
Dust and dirt is a common enemy of solar power systems, and its effects go beyond the accumulation of grime. It’s true that sun rays may still pass through a thin layer of dust, and wind or rainwater can quickly sweep most of it off. But if your PV array is located near dustier areas such as farmlands, main roads, cement factories, and quarries, the story changes. Your solar panels will need special attention and frequent cleaning as they have to contend with far more dust and dirt.
Now, you may be thinking, “Wait. You told that customer to use water to clean their panels. Why is it on the list?”
Fair question! The issue has to do with the pooling of cleaning or rainwater on horizontal solar arrays. Apart from simply reducing your solar energy generation, the water layer can leave a muddy residue after evaporation, necessitating more frequent cleaning.
Do Solar Panels Need Cleaning?
Like anything that stays outside every day and night, solar panels will eventually accumulate dirt. But how frequently you may have to wash your panels depends on several factors, including:
- System design
- Installation angle(s)
- Size/number of panels
- Types of dirt
- Duration between thorough cleanings
So, do solar panels need cleaning? Our definitive answer comes in three parts:
Answer #1: Yes, and You Can Do It Yourself
Bird droppings and other dirt agents can affect your solar panel’s performance, especially if your panels lie truly horizontal on the roof. That’s where washing the panels becomes important, though it doesn’t have to be a thorough or routine cleaning in many cases.
As we suggested to the customer with the white powder on their panels, cleaning your solar panels is usually a relatively easy task. All you need to do is to spray the panels with average-pressure water from a well-angled garden hose while standing on the ground.
If you want extra cleaning power, a long-handled squeegee or soft brush plus a medium-pressure hose nozzle can work wonders. With the nozzle, directing the spray will become easier. You’ll then wipe off the water using the squeegee for maximum electricity production. This approach provides even more cleaning power, but it does depend on the angle of your roof, roof height, and panel placement, because not everyone will be able to reach their roof, even with a long handle.
Answer #2: Yes, but You Don’t Need to Do Anything
Maintaining your panels is essential, but you don’t need to clean them as often as most people think. You may need to remove the occasional buildup of leaves, bird droppings, and other debris to maximize the amount of sunlight exposure your panels receive. Any regular wind and rain will typically sweep off most of the dirt, so it’s better to let nature take its course and only do one thorough cleaning every year to maximize energy production.
When it comes to doing any thorough cleaning and maintenance, it’s best to hire a professional with the knowledge and tools to get the job done safely and correctly the first time.
Answer #3: No, Unless Something Really Bad Happens
Researchers at the University of California left solar panels on a roof for 145 days without cleaning. Their findings? The panels’ energy generation efficiency dropped by 7.4%.
It may surprise you that the efficiency of your solar panels can remain intact over a long period, considering all that exposure to debris, dust, heat, and rainwater. But you can trust your panels to withstand the regular wear and tear of the elements.
Solar companies employ only the leading technologies and engineering skills when manufacturing their products. Their design processes usually account for the effects of dirt, water, and pollen from everyday use.
You still need to be on the lookout for any obvious structural issues with the panels, supports, and roofing.
Can Cleaning Solar Panels Improve the Performance of PV Systems?
As we’ve seen so far, the short answer is, The impact of dirty solar panels on solar power production depends on various factors. But we’re interested in the long answer, right? Let’s dig into the science and math a bit:
An experiment involving solar panels on a low-slope roof sought out the difference in energy output before and after a thorough cleaning.
The researchers found an average 3.5% boost in energy production (the amount of power produced over time) after cleaning the panels using a soft rag and water. The implication here is that the energy yield increase was low, despite the high amount of dirt accumulation.
Things became interesting when heavy rain did the cleaning job. The average performance increased by only 1.9% after rainwater pounded on the dirty panels. What does that mean? A good shower from the skies can take care of some cleanup, but it’s not as effective as the proper equipment and some elbow grease.
You may want to check how much your dirty solar panels are costing you in terms of energy generation. Here’s a simple formula for determining the value of solar panel cleaning:
Yearly Energy Production (kWh) × Production Loss From Dirty Panels × Electricity Cost per kWh
For example, if your residential solar energy system can produce 10,000 kWh of electricity per year, and you assume a 5% loss of production due to panels being dirty, and you pay 20 cents per kWh for electricity from your utility, your yearly cost of electricity loss from dirty panels is as follows:
A 5% electricity production loss might not sound like a lot, but it can definitely add up, and suddenly you’re paying way more to your utility company on your electricity bill than you need to be.
The Science of Cleaning Your Solar Panels
Yes, rain helps wash solar panels and keep dirt at bay, but it comes with several downsides, which can lead to noticeable performance problems on panels set at low angles:
- Rainwater comes laden with pollen and dirt
- It can pool on the surface of your panels, especially if the glass surface sits lower than the frame
- Once the rainwater evaporates, it can leave behind a muddy residue
So, should we rule out the need for cleaning solar panels? Not yet. Researchers at Google’s solar farm have a different story.
In one set of their experiments, they studied 1.6MW of horizontal solar panels on flat carports in Mountain View, California. These panels operated untouched for 15 months.
After cleaning them, they realized that the energy production from their carport solar panels had doubled overnight! Eight months later, they cleaned those same solar panels and learned that the output had gone up by 36%.
So, what’s our conclusion? All solar panels still need frequent cleaning, especially if they’re horizontal or almost horizontal on your roof. If yours are tilted appropriately, a reasonable amount of rainfall will get them mostly clean, but a scheduled annual visit from cleaning professionals may further help your overall renewable energy output.
How Can I Clean My Solar Panels?
Cleaning your solar panels doesn’t have to be extensive or risky work. If you’ve decided to clean your panels yourself, what matters is that you follow these cleaning tips to keep both you and the solar system safe.
When in doubt, just remember that you can always call in the professionals to get the job done safely and efficiently. Because some solar installers are only focused on new installations, they don’t all offer services like solar panel cleaning. If that’s the case, rest assured that Palmetto can still provide any of your solar service and maintenance needs.
Tips for Cleaning My Solar Panels
Before setting out to clean your panels, you must keep in mind one crucial point: Avoid scratching or damaging the glass at all costs. You don’t want your energy production to plummet.
When cleaning solar panels, you will always be gentle with them by using these solar panel cleaning tips and tricks:
- Solar panel models are not all created the same. It’s prudent to check with your product’s manufacturer to see if they have specific instructions for cleaning.
- Consider using a garden hose first. But if grime and dirt have built up on your equipment, it’s time for a thorough cleaning.
- Most likely, the only equipment you need is a bucket with clean, warm water, a soft cloth, dish soap, and a soft brush or squeegee.
- Pick an evening, a morning, or a cool day to do the cleaning. You don’t want to get burned by hot panels on a sunny day. If it’s too sunny, the soapy water can evaporate before you get time to wipe it away, which can leave a smear or residue that can reduce your panels’ efficiency.
- Avoid splashing cold water on a hot glass surface. It can lead to cracks due to sudden contraction.
- Apply the warm water and dish soap on the panels’ surfaces using a soft cloth or sponge. Do NOT clean the wiring underneath.
- Use a squeegee to get rid of dirty water.
- Never step on your panels, as this can damage them and cause premature failure.
- Avoid brushes with sharp bristles that can scratch your solar glass surface.
If you live near an airport or a route frequented by trucks, expect to find a few oily stains on your panels. In this case, you can use a rag and a little isopropyl alcohol to remove them.
Pro Tip: Strong cleaning fluids should not touch your expensive investment at all. Harsh chemicals and liquids like laundry detergents, ammonia, and acids can react with or streak the glass surface, leading to damages and a loss of energy production.
How Often Should I Clean My Solar Panels?
In most cases, you only need to clean your solar panels once or twice per year. We recommend scheduling your annual cleaning routine during the spring. That avoids the heat of summer and harsh elements of winter.
However, your solar panels might need extra attention in some locations. For example, the Southwest US experiences more significant dirt accumulation because of limited rainfall. Also, panels in homes near airports, factories, freeways, and other sources of pollution will need more frequent cleaning.
Winter and autumn are other special cases. Removing heavier-than-average snowfall and leaves can boost your solar performance significantly.
Do I Clean Off Snow?
We get it. heavy snowfall days can make anyone nervous about their system not generating enough energy. However, snow on your solar power panels usually melts away quickly, thanks to the heat created by the solar panels, and their slick surface. Snow on a panel melts faster than on an empty roof due to the high difference in heat between the two surfaces.
But if the snow is taking longer to melt and your battery storage is running low, you don’t have to wait. You can brush the snow off your panels to get them back to producing power right away.
Make sure you use the right equipment to avoid damaging your investment and compromising its warranty. Thus, shovels, standard brooms, and other non-specialized tools should not come anywhere near your panels. A suitable snow roof rake created for the task will come in handy here. They typically cost around 30 to 150.
Can I Use a Pressure Washer When Cleaning My Solar Panels?
No. Not at all. High-pressure water is among the biggest enemies of your solar equipment.
First, high-speed moisture can quickly force its way through the seals around the frames and get into vulnerable technology. These water leakages can promote corrosion of the fine wires, which leads to the failure of the solar panel and its photovoltaic cells.
Also, the glass surface can break under high water pressure. We hear you asking, Why then don’t we see damage resulting from continuous rainfall pounding on the glass? That’s because panels are designed to resist hours of heavy rain falling across a wide surface area. But washing the panels with high pressure directs a focused beam of water in a highly concentrated spot, which creates an increased chance of stressed areas that can crack.
What is Localized Soiling?
Localized soiling of solar panels is when material like bird poop, leaves, and any other heavy blockages get stuck on your panels, but only cover part of the panel. Compare that to general soiling, where material like dirt and dust covers the entire panel surface.
When rain and wind fail to remove localized soiling, this sort of debris may block some parts of the equipment, leading to hot spots.
Your panel is made of several individual cells (60 in most cases). When localized soiling blocks sunlight from reaching one of the cells, its energy production drops. However, full current flowing from the adjacent cells may pass through the affected one. The result is overheating at that cell, a phenomenon that can cause damage to the panel.
Yes, modern solar panels come with multiple built-in bypass diodes to keep hot spots at bay. But those extra-dirty areas can still lead to damage over time that can increase your solar panel maintenance cost.