Solar panel cleaning: What you need to know

While a solar energy system is generally a "set it and forget it" approach that allows you to produce renewable energy for your home passively, you may need to freshen up your panels occasionally. While it's not necessary to clean solar panels, you may be losing value and efficiency by not doing so. In this article, we'll answer some common questions solar panel system owners have about solar panel maintenance and how to perform it safely.

Your solar panels must be exposed to sunlight to produce power. However, solar panel cleaning is generally unnecessary unless you live somewhere with high amounts of smog, dust, dirt, grime, or sand blowing around. In most cases, occasional rain will be enough to naturally and safely keep your solar panels clean and free of debris that could lower production. But a good clean every once in a while can help to maximize your panel's photovoltaic (PV) production. So if you need or want to clean your solar panels, we're here to help you determine the best way!

Just like washing your car, you can DIY solar panel upkeep, but there are also professional solar panel cleaners to make it easier. For a small fee, your solar installer may even do it for you. If you have a rooftop system, enlisting a cleaning service might be a good idea, if only for safety precautions. A professional solar panel cleaning company may not do a significantly different or better job than you can, but they're better equipped to clean and maintain rooftop units safely. For ground mount units, it may not be worth the service fee when you can safely and effectively clean your panels with a water hose, some dish soap, and a soft rag.

Types of professional cleaning

Many different types of professional cleaning companies can help you. Robotics companies use semi-autonomous machines to clean without as much direct personal work involved. Some maintenance companies also use soapless brushes and sponges to clean panels to avoid potentially harmful residues. Other high-tech cleaning options are developing, including waterless vibration and nanoparticle coatings.

Does your solar lease cover panel maintenance?

Solar lease agreements often include a maintenance clause if your panels are leased. Some companies will perform regular maintenance on their panels, including washing services, while others will repair damages the customer reports. It's important to remember that solar panels generally require little maintenance, and spraying them down with a hose occasionally can do the trick.

Here's a step-by-step guide on how to clean your solar panels:

1. Shut off your solar panel system – this will help ensure your safety and that equipment is not damaged.

2. Use a soft brush to clean the surface of your dirty solar panels to remove debris like dirt and dust.

3. When cleaning your panels with water, use a standard garden hose and soapy water. You need to purchase no particular cleaning solution to clean your panels; regular dish soap will work perfectly. You should avoid using a high-pressure hose that you might use to do things like power washing your house, as they can create cracks or otherwise damage your system.

4. After you have finished the cleaning process, monitor energy output to see the difference in efficiency that cleaning has made.

When cleaning your solar panels, the most important consideration to remember is that scratching or damaging the glass in any way will reduce a panel's energy production. It's best to approach panel cleaning the same way you might clean your car. Dish soap and clean water applied with a soft sponge or cloth is the safest and easiest cleaning method. It may also be helpful to use a squeegee to remove dirty water. Remember: Avoid damaging or scratching the glass at all costs.

On rare occasions, oily stains can appear on your panels. You might find these if you live near a common truck route or an airport, and they can be tackled with a bit of isopropyl alcohol and a rag. You must avoid using strong cleaning detergents, which can streak and damage the glass and impact the efficiency of the panel.

The frequency of solar panel cleaning depends primarily on where you live:

• In desert climates, including the U.S. Southwest, more regular cleaning is needed due to the large amount of dust and sand that could affect a solar energy system's output.

• Solar panels in polluted areas near highways, factories, and airports should also be cleaned more frequently to avoid residue buildup from pollutants that could result from heavy machinery nearby.

• Solar panels should be frequently cleaned in heavily wooded areas to prevent obstructions due to overgrown vegetation and bird droppings.

In the winter, snow on solar panels generally doesn't need to be removed – it will typically slide off on its own. Most panel installations are tilted at an angle, and snow will naturally slide off as it melts. If snow persists on your panels, you can invest in tools like a solar panel snow rake, making it easy for homeowners to remove snow covering on solar panels safely. Don't use a standard broom, shovel, or another non-specialized tool to remove snow from panels; they can scratch the panel glass and lower your solar power production.

What is the best thing to clean solar panels with?

Dish soap and a soft sponge or rag are the best to clean solar panels.

Can I clean solar panels myself?

Yes, you can clean solar panels yourself by filling a bucket with water and using dish soap and a low-pressure hose.

Does cleaning my solar panels void my warranty?

Keeping your solar panels clean will not automatically void your warranty, but be sure to avoid using harsh chemicals and pressure washers or other water-fed poles that could potentially crack or otherwise damage your panels. Improper cleaning practices can void your warranty, so be sure to read the details before you jump into cleaning yourself.

Can you use Windex on solar panels?

Windex is a cheap and widely available cleaner that is excellent for cleaning glass surfaces such as those on solar panels to ensure they run efficiently.

Is it okay to pressure wash solar panels?

While they may be suitable for cleaning other parts of your home, you should never use a pressure washer on solar panels to avoid damaging them and creating cracks.

What is the cost of cleaning solar panels?

A professional cleaner may charge between $150 and $300 to clean solar panels. This varies widely on the type of panel, the degree of cleanliness, and how many panels you have. Costs range from $15-$30 per panel.

Does cleaning your solar panels make a difference?

While debris being cleaned off naturally by rain will help, making a concerted effort to clean your panels will increase solar panel performance.

How often should solar panels be cleaned?

It is recommended that you clean your solar panels every six months to a year to maximize the efficiency of your solar panels. 

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