Clean Solar Panels (When, Where, How)

Cleaning solar panels isn’t as hard as many people think, but there are a few things to keep in mind. Here’s everything you should know about this process.

Man Cleaning Solar Panels With A Brush Pad
Man Cleaning Solar Panels With A Brush Pad

What Is the Best Way To Clean Solar Panels?

The best way to clean solar panels is by following these steps:

  • Wipe off all debris on the panels with a long brush
  • Spray the panels with water or a mild cleaning solution
  • Brush the panels clean, applying more water as needed
  • Dry the panels, either naturally or with tools

Solar panels are often in areas that are hard to reach, so hoses and tools that can attach to long poles are also helpful.

Is Solar Panel Cleaning Worth It?

Yes. Solar panels don’t require much maintenance unless you’re in a particularly dry or dusty area, but it’s worth cleaning them occasionally to keep them in good shape. 

Does Cleaning Your Solar Panels Make a Difference?

Yes. Dirt and other debris on top of a solar panel block sunlight from reaching it, reducing the panel’s overall efficiency. 

It means it takes longer to fill batteries or even reduces the number of things you can run at one time. The drop in efficiency isn’t as noticeable with new panels, but it can make a big difference for older, less-efficient panels.

Cleaning Brush On A Solar Panel
Cleaning Brush On A Solar Panel

How Often Should Solar Panels Be Cleaned?

You should clean solar panels as often as necessary. For most panels, this is once or twice a year. However, panels in dusty or dirty areas, such as near construction sites, may need more frequent cleaning.

Is It OK to Power Wash Solar Panels?

No. While power washers are suitable for cleaning most things outside the home, they can bend, crack, or even destroy solar panels.

How Long Does It Take To Clean a Solar Panel?

An experienced person can clean a single solar panel in about 3-4 minutes. The cleaning process includes brushing off the panel, spraying it with water, and wiping it down to remove excess dirt.

At this speed, cleaning a typical 32-panel solar panel array takes about two hours.

Do Solar Panels Require Servicing?

Most solar panels don’t require any servicing after installation except for cleaning. However, they may need care if you face environmental threats, such as severe windstorms that could throw rocks and other debris into the panels.

How Much Does It Cost To Clean Solar Panels?

If you’re cleaning panels yourself, the main cost is time. The price of water and a small amount of soap is negligible on practically any budget, though you may need to get a long ladder to reach the panels.

If you’re hiring a contractor, most people pay around $200 for this service. Prices may drop a little for small arrays or go up if you have an unusually high number of panels.

Cleaning Solar Panels On A Cargo Van - Sol Voltaics: Solar Panel Information
Cleaning Solar Panels On A Cargo Van

What Problems Do Solar Panels Face?

Solar panels don’t face many problems unless installed in risky areas. Places with heavy snowfall or frequent windstorms may not be suitable for solar panels.

Does Mold Grow Under Solar Panels?

Yes, mold can grow under solar panels. The area beneath panels tends to be shaded and may attract moisture, which mold sees as an ideal environment. Occasionally cleaning the area can limit the growth of mold.

Having a roof that mold dislikes can also help keep things under control. Metal roofing is especially good at deterring mold growth, though not appropriate for all areas.

Does Dirt Affect Solar Panels?

Yes. Dirt on top of a solar panel can block sunlight and reduce the panel’s effectiveness. Dusty areas tend to have more problems with dirt because it can go up into the air and land on the panel. Wetter regions don’t have as much trouble with this.

Cleaning Solar Panels
Cleaning Solar Panels

Solar Panel Cleaning Questions

Here are some common questions that people have about cleaning solar panels.

Can you clean solar panels with tap water?

Yes, but only as long as your household has soft water. If you have hard water in your home, the extra minerals could damage your solar panels over time.

Is it OK to squeegee solar panels?

Yes. A squeegee is a great way to get water off the top of a solar panel and help it dry faster. Water can damage panels if you’re cleaning them on hot days, so removing the water yourself can help protect your solar panels.

Can you walk on solar panels?

You can walk on most solar panels, but it’s better to avoid this unless you have to. Walking on panels can damage them or leave dirt and other debris behind, defeating the purpose of cleaning them. It’s always better to clean panels from a distance with long-handled tools.

Since many solar panels get installed at an angle, they may be too steep to walk along safely. Using tools makes cleaning panels considerably safer.

Can you use vinegar to clean solar panels?

Yes, but only if you dilute it with water. Concentrated vinegar is too strong for solar panels and may damage them. 

Weakening it to at least a 1:8 ratio (about a quarter cup of vinegar per two cups of water) and adding half of a teaspoon of liquid detergent creates an excellent cleaner for solar panels.

How do you clean algae off solar panels?

The best way to clean algae off solar panels is similar to cleaning off anything else: use a gentle brush to sweep off loose debris first, then use your cleaning liquid and wipe it dry.

A little elbow grease when you’re drying won’t hurt solar panels, but try to avoid using anything too abrasive. A proper cleaner should loosen and remove algae with little difficulty.

How do you remove lichen from solar panels?

Cleaning lichen off solar panels is essentially the same as cleaning algae off. However, it’s vital to remember that lichen may be hard to remove with tap water alone. Adding vinegar and a little detergent to your cleaning liquid should make it significantly easier.

Can I clean solar panels with alcohol?

Yes, but alcohol is more likely to cause damage than some other cleaners. If you have oily stains on your panels, isopropyl alcohol will remove them. Start by diluting the alcohol to a 1:10 alcohol-water ratio and see if that works, and make it a little more concentrated if necessary.

How do you clean solar panels with hard water?

Don’t use hard water to clean solar panels unless you have no other option. If you only have access to hard water in your home, look into installing a system that can soften your home’s water.

Make sure this applies to your hoses. Stopping hard water inside your home may not affect your outside faucets, and that’s what we care about for cleaning solar panels.

Can I use Windex on solar panels?

Yes. Windex and other specialized glass cleaners are generally appropriate for use on solar panels. They deal with various problems glass may face, although they may also require a little scrubbing to get everything off.

Although these are effective, they can also get expensive if you buy them in bulk to clean a large solar panel array.

It’s more affordable to buy some vinegar and create a cleaning solution, only switching to Windex or a similar product if you encounter a particularly tough spot.

How To Clean Solar Panels on Roof

There are several different ways to clean solar panels on a roof.

Solar Panel Cleaning Service

Hiring professional solar panel cleaning services is the easiest way of cleaning solar panels, especially if your array is in a difficult-to-reach location. 

A typical home array costs about $200 across most of the country, although expensive or challenging areas may increase the price.

Commercial systems with more panels cost more to clean than homes. The final price depends on the overall size of the system and any special considerations the cleaners need to keep in mind.

It usually doesn’t require internal access to a structure to clean solar panels, so most cleaners can get the job done even if you’re not on-site. However, they do assume you have access to water. If you don’t, make sure to mention that when hiring the cleaners.

Cleaning Solar Panels With Brush And Squeegee
Cleaning Solar Panels With Brush And Squeegee

DIY Solar Panel Cleaning

If you don’t want to hire a cleaning service, the best alternative is to clean the panels yourself. It is a straightforward process involving climbing up to the panels and using your chosen tools and supplies to clean them off.

Safety is paramount when cleaning solar panels. The biggest threat most people will face is losing their balance and falling. Even if climbing up is safe, pushing too hard against a roof with your cleaning tools could lead to severe injury or death.

While this is a real risk, it’s comparatively easy to mitigate with good situational awareness. If possible, attach yourself to the roof with an appropriate harness or safety line. A firm anchor that stops you from falling is usually the safest choice.

Whether or not you have a harness, brace any ladder you’re using securely against the ground. A ladder with four feet is better than one with two feet. Have someone stand at the bottom of the ladder to brace it in the event that you push yourself away.

Finally, consider any site-specific risks. The guidelines above are appropriate for most situations but do not account for any unique threats or problems.

For example, if you can access every solar panel by foot and don’t need to climb, you don’t need to worry about harnesses or ladders. If you’re trying to clean a solar panel 20 floors up a skyscraper, you may need a lift platform instead of a ladder.

Solar Panel Cleaning Kit

Some stores sell solar panel cleaning kits. These typically include a small amount of cleaner and several tools, including brushes. The best kits are those sold by the panel’s manufacturer because those are tested and designed to work with your panels.

Solar Panel Cleaning Brush

The best popular solar panel cleaning brushes have a hose attachment at one end. These allow you to get water up to the highest solar panels without difficulty, although you will need a hose long enough to reach them.

Brushes without hose attachments exist, but these are significantly less effective at a price that’s only slightly lower, so they’re not a good deal.

Remember that you can usually attach a bottle of cleaning fluid to the end of a hose before attaching it to the brush itself. This method is the best way to get your cleaning liquids onto a solar panel.

If you’re getting a brush with a hose attachment, look for a high-quality brush that can handle the water pressure and any awkward maneuvering. Aluminum is a good choice for most homeowners, but a sufficiently durable plastic brush will also work.

Solar Panel Cleaning Robot

Solar panel cleaning robots are a relatively new technology that helps to automate the process of getting panels clean.

These aren’t practical for most homeowners because they’re too expensive for a small array of panels, but they can save you a lot of money if you have an unusually high number of solar panels on your property.

Robots may also be helpful for properties where the panels are too large to comfortably reach with a brush, even on a long extension.

A good robot can clean around five thousand square yards of solar panels in one day. For comparison, an average 5 kWh household array is about thirty-three square yards.

Commercial Solar Panel Cleaning Equipment

Finally, it’s worth considering whether you want to invest in commercial cleaning equipment. Most homeowners don’t need to bother because it’s hard to avoid taking a loss if you only clean things once or twice a year, but businesses may want to look into this.

Commercial solar cleaning equipment includes higher-quality brushes, motorized systems, and better cleaning chemicals.

Sources:

Solar Panel Maintenance FAQ

Do I need to clean my solar panels?

Unless you live in an area that doesn’t get much rain, or you live in an area with high amounts of smog or dust, cleaning solar panels is not usually necessary. Fine dust or dirt do not have much of an effect on the efficiency of your panels, although this can eventually build up into hard grime that will begin causing problems. We recommend cleaning your panels once or twice a year just to be safe. 

How do I maintain my solar panels? 

One of the best aspects of solar panels is that they are basically maintenance-free; you simply set and forget. However, it’s good to make sure they are not being shaded too much and to keep an eye on your charge controller to make sure the batteries are being charged properly. 

Do solar panels need to be serviced? 

Solar panels have no moving parts and are thus basically maintenance-free! They do not need to be serviced at all, other than occasional cleaning. Inverters and batteries are arguably the most vulnerable part of your solar system and will need serviced or replaced every decade. 

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