Keeping your solar panels clean involves using a soft brush or sponge, a squeegee, water, and a suitable solar panel detergent to scrub the grime off, rinse and dry the panels.

To remove any dirt or grime buildups, you’ll need a sturdy, secure ladder (if the array is roof-mounted) and some basic cleaning equipment. These include a soft, long-handled brush, a hose pipe with an adjustable spray head, a long-handled squeegee, and a solar panel cleaning solution.

The cleaning process starts with electrically isolating the panels then gently hosing off any loose dust, leaves, bird droppings, and other grime. When using the hose or brush on the panels, try to avoid getting the back surfaces and electrical connections wet.

When the excess dirt is removed, you can apply the cleaning solution to the panels with a spray bottle or a hose mixer. Then use the long-handled brush to carefully and gently scrub the remaining dirt off the panels. Rinse all the dirt and cleaning solution off with the hose and use the squeegee to remove the excess water.

Wait a couple of minutes for the panel surfaces to dry completely and visually inspect the panel surfaces for any remaining dirt. If you’re satisfied with the result, you’re done!

Why Are Clean Solar Panels So Important?

How to Clean Solar PanelsIt’s hard seeing anything through a filthy window, and the same principle applies to solar panels. Solar arrays are only as effective as the volume of solar radiation they’re exposed to. The more sunlight that reaches the photovoltaic (PV) cells through the glass covering of the panel, the better they work. Try and imagine how well your solar panels would work if you painted them black!

A layer of dirt and grime on the surface of the glass covering of the panels can reflect more solar radiation than it transmits. Generally, moderately dirty panels would suffer an energy output loss of around 4 percent. However, if the panels get really dirty, your solar system could lose upwards of 20 percent of its peak solar power potential output. And that is a conservative figure and can play havoc with your system and its role in your property value.

The average solar power user is constantly battling with shading, short winter days, and overcast or cloudy days, all of which rob their solar system of optimal efficiency. So, neglecting to keep your solar panels clean could potentially lead to unnecessary increases in those energy production losses.

What Makes Solar Panels Dirty?

The answer to this question is pretty broad and depends largely on where you live. Here are the most common causes of solar panel contamination: dust coming out tops as the main culprit.

  • Dust.
  • Environmental debris (leaves, twigs, flower litter)
  • Salt deposits.
  • Bird droppings.
  • Pollen.
  • Atmospheric pollution.
  • Ash and soot.

Does Rain Do a Good Job of Cleaning Solar Panels?

Yes and no. Rain showers effectively remove dust deposits, leaves, and some of the more stubborn soiling from solar panels. Unfortunately, rainwater also carries airborne contaminants and can actually contribute to dirty solar panels. If your only real source of soiling is dust and you live in a high rainfall area, those downpours will be your friend. However, you will have to clean your solar panels yourself regularly actively.

How to Clean Solar Panels Effectively and Safely

NOTE: Before we dive into the actual cleaning, please take note of the following points.

  • Safety is paramount! Always isolate your panels before starting a cleaning session. When working at heights on roof-mount arrays, always observe ladder and general safety regimens.
  • Solar panels are sensitive devices. Do not use sharp or highly abrasive cleaning equipment on them. The same applies to corrosive or aggressive cleaning solutions.

What You’ll Need to Clean Your Solar Panels

What You'll Need to Clean Your Solar PanelsFor the most part, all of the materials and equipment you’ll need can be found in any hardware store, supermarket, or online. There are also many really great solar panel cleaning kits out there, which include most, if not everything, you’ll need.

The gear you’ll need can be broken down into 3 categories — Access, personal protective equipment (PPE), and cleaning materials.

Access Equipment

Step Ladder

If you don’t already have a good ladder, this will be the biggest financial outlay. Sliding extension ladders are better than folding or telescopic types, although all types are suitable. Ladders with gutter hooks or stays, stand-offs, and extra supporting legs are the most stable.

As a rule of thumb, you’ll need approximately 12-feet of ladder length for each level of your home. So, you’ll need a 24-foot extension ladder to reach the average double-story roof. The carrying capacity of the ladder should be around 330 pounds (150 kg).

Note: Telescopic ladders are best restricted to around 12 to 15 feet.

PPE Equipment

Safety Harness

A safety harness or fall arrestor is an essential part of your safety gear and should ideally be a full-body harness with at least 2 tether D rings.

Eye Protection

Although the solutions you’ll use are gentle on the panels, they’ll do your eyes no good if you get an accidental splash in the face. If you wear spectacles, choose eye protection with oversize frames that you can wear over your specs.

Gloves

Flexible and breathable medium-duty gloves with moderate chemical resistance are perfect for protecting your hands against cuts and exposure to cleaning solutions.

Respirator or Face Mask

Most of the solutions you’ll use to clean solar panels are not highly corrosive, but it is good practice to prevent fume inhalation.

What You’ll Need to Clean Your Solar Panels

Long-Handled Squeegee/Sponge

Most solar panels in residential settings are around 5 feet high and 3 feet wide. If you have multiple rows of panels, you’ll need to reach around 10 to 12 feet to clean the top row. try to choose a sponge with an extension handle that will cover your solar panels without you having to get on the roof. Here is a good combination of squeegee and cloth with a 24-foot extension.

Garden Hose and Spray Head

Try to make sure your garden hose pipe is long enough to reach the full length of your solar panels.

Solar Panel Cleaning Solution

Although you can use conventional window cleaners, it’s better to use a dedicated mild detergent. These are often available as concentrates in a hose spray applicator. We strongly suggest you use one of these. They are very convenient and are the best option for getting the solution evenly distributed on the solar panels.

Cleaning Your Solar Panels

Cleaning Your Solar PanelsThe actual cleaning process is the same for roof-mount and ground-mount solar arrays, with the obvious excepting of ladder work for ground-level arrays. For this guide, we’ll cover the more challenging roof-mount array process.

Note: The panels will get very hot on sunny days, which makes cleaning difficult. So, it’s best to plan your cleaning session for the early morning or late afternoon.

If you want to get the job done smoothly with a minimum of ladder gymnastics, it’s a good idea to get completely organized before you start. Make sure you have all your equipment on hand and prepared. Then go ahead and isolate the solar panels.

Now decide on a logical starting point and direction of movement during the cleanup. This would typically be on the end of the array closest to the water source. Attach the spray head and pull enough hose off the roll, and lay it out in a way that makes it easy to lift.

Then you can get your ladder set up securely with the stays or gutter hooks firmly n place. Do not put the feet of the ladder in any hose coils. Make a trip or two up the ladder and put your squeegee/sponge and filled hose mixer bottle on the roof. Put on your safety glasses, respirator, and gloves, strap on the harness, grab the end of the hose, and up you go!

Initial Rinsing

When you get into position, tether the safety harness to a secure mounting point and get into a position where you are comfortable with firm footing. Now use the spray to rinse off any loose dirt, leaves, or bird droppings from as many panels as you can comfortably reach with the brush or sponge. If it is a scorching day, you may have to reduce the number of panels you clean on each pass as they’ll dry too quickly.

Note: When rinsing the panels, always work away from yourself and from the top of the panels to the bottom.

Washing

While the panels are still wet, swap out the spray head for the mixer bottle and apply the detergent to the panels. Hang the hose up, and then use the extension brush to scrub the panel surfaces clean gently. It’s often difficult to see if you gave missed spots while the panels are wet. So before you move on, squeegee as much water off the panels as possible and quality control your work. If necessary, repeat the process if you have thick layers of dirt.

Moving On

When you’re happy with your first pass, move the ladder adjacent to the last panel you washed. Now climb up and repeat the washing process. Placing the ladder in this way will always have you rinsing and washing away from the clean panels avoiding having to do double work. Repeat the whole cycle until all the panels in the array are clean.

Reconnect the panels, and you’re done!

Periodic Cleaning

It’s good practice to hose the panels down between deep cleans regularly. This can often be done from the ground, although using the ladder is a better option with less chance of spraying water under the panels and onto sensitive electrics. As a matter of course, doing this makes deep cleaning solar panels easier and ensures optimum performance from the system.

Maintenance-Centric Installation Tips

Whether you have a roof or ground-mount array, there are a couple of things you can do to make regular solar panel maintenance, such as cleaning a whole lot easier. These can be done at any time, but it’s a good idea to do them during the installation.

  • Install a panel location water point. Running a water line up close to the one end of the array will allow you to use a far shorter hose and generally make the process far easier. The line can be terminated with a faucet with a female quick connect hose fitting would also be a great idea. You could even leave the panel cleaning hose permanently connected and coiled up safely under the eaves if possible.
  • Install brace and hook points. With roof-mount arrays, it’s great to mount brace and hook-up fittings such as ring bolts, tie-down rings, and heavy-duty cup hooks at regular intervals along the run of the array. These are handy additions that allow you to secure your ladder, attach your safety harness tether and hang the hose or other gear while cleaning or working on the panels.
  • Install a custom walkway. This is the ultimate nice-to-have but probably wouldn’t suit most solar system owners. However, if your budget, home structure, and aesthetics allow it, a walkway that spans the array with a permanent or attic-style pull-down ladder would be an awesome addition.

Using Solar Panel Cleaning Services vs. DIY

DIY cleaning solar panelsAlthough cleaning solar panels yourself is relatively straightforward, it won’t suit all residential solar owners. If your roof is too steep or too high or if you are not physically able to get it done, professional cleaning services are probably the right choice.

In addition, many folks don’t want to have to buy gear they’ll use once or twice a year. That’s understandable, considering a good ladder can cost close to $1,000.

And talking money, how do the two options stack up against each other. Keep in mind that the gear cost is essentially a one-off expenditure outside of the detergent and replacement sponges. We’ll use the items listed in our guide as an example of setting up to clean your solar panels solo.

  • DIY option. Total DIY gear cost – $550 – $650
  • Professional solar companies cleaning services option. An annual inspection – $150 (some companies insist on this), per panel charge – $3 to $10 per panel (the average household has between 15 and 25 panels), average flat rate charge – $150 to $350. The average cost of a pro cleaning job – $250.

Considering the average solar install has a lifespan of up to 30 years, it’s clear that, if you can, a DIY job is a way to go.

In Conclusion

It’s a no-brainer that cleaning solar panels is a critical component in ensuring optimal system performance. It’s also clear that it’s not that hard to do and that if you’re able, it’s best to clean your solar panels yourself. Hopefully, this guide will make that process a little easier for you. Good luck!

If you have any advice or questions, please post them in the comments section below.

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