What Can You Clean Solar Panels With? Efficient & Cheap Methods!

Solar panels are four times more efficient today than when they first became commercially available in 1950.

The most efficient solar panels on the market today convert sunlight at around 22% and have a power rating of over 400 watts! That is a remarkable improvement in cell technology considering the first solar cells produced less than five watts.

With that said, even the most efficient solar panels will not work at their optimum if improperly installed or maintained. The design and maintenance of a solar system are possibly more critical to the output of a system than the efficiency or size of the solar panels.

Poor configuration and maintenance can lead to system losses of up to 24%. Most of which are preventable. One commonly overlooked area of solar panel maintenance is cleaning. Just keeping solar panels clean can improve performance by between 4 to 21 percent.

In this guide, we look at how you should clean a solar panel system. What products should you use and how effective are glass cleaners for example?

What’s The Best Product To Clean Solar Panels?

In the majority of instances, the best thing to use to clean solar panels is water. Rainwater is sufficient to wash off most of the dirt on a solar panel. For tougher dirt that does not wash off easily with water, very mild soap or detergent should be used.

Depending on your location, you can rely on rainwater to do the job of cleaning your solar panels. Some states and cities in the U.S are dirtier than others due to heavier pollution and smog. California for example has thicker air pollution due to the high number of vehicles.

Several scientific studies show a link between air pollution and a reduction in solar energy. According to one study, air pollution absorbs and disperses sunlight, reducing how much reaches the Earth’s surface. This has significant implications for solar panels. Essentially what it means is the more polluted the location, the less solar there is. Source

DIRTIEST STATES IN THE US	DIRTIEST CITIES IN THE US
New Jersey	Newark
Texas	Houston
Delaware	Los Angeles
Rhode Island	San Bernadino
California	Oklahoma
Pennsylvania	San Antonio
Indiana	Las Vegas

The link between air pollution and solar energy production demonstrates why it’s important to keep solar panels clean.

We also highly recommend that you check out our post “What Are The Best Natural Products To Clean Solar Panels With? (Brief Guide!)“

How Do You Clean Outdoor Solar Panels?

Solar panels should be cleaned with warm water and a soft cloth to wash away dust. Organic waste that clings to the solar panel may require soap. Care should be taken to avoid using any material, such as a hard brush, for example, that may scratch the glass cover of the solar panel.

Dirt on a solar panel can create shading effects. This is similar to how having a tree branch or adjacent structure like a chimney casting a shadow on the solar panels.

Shading can reduce solar panel output by anywhere from 30 to over 90 percent depending on how severe it is. It can also potentially damage the solar cells by increasing internal resistance in the cells and creating hot spots.

The shading effects of dirt are generally not as severe as what you will get from a solid object. In most cases, the impact on production is less than 4 percent. This depends on how much and what type of dirt it is. Typically, the dirt on a solar panel is either debris, dust, or organic waste matter.

Cleaning debris from a solar panel

Debris can be anything that collects on the surface of the solar panels like leaves or small branches. The best way to keep debris off solar cells is to install the panels at an angle. This allows the debris to simply roll or get blown off.

This is one of the reasons why it’s better to install solar panels at an angle than lying flat. The other reason is the improved absorption of sunlight you get from tilting the solar panels.

Dust is much simpler to clean. To clean the dust of a solar panel these are the steps you would normally follow.

1. Always clean the solar panels in the early morning or late afternoon. This is because the solar panels get very hot. This not only makes them difficult to handle but also raises the prospect of cracking the glass cover if cold water is used on the hot panel.
2. An additional safety precaution is to turn off the solar panels to prevent there being any risk of electrocution. Solar panels produce very high voltages. Turning the system off reduces any chance of causing a short circuit should there be any exposed wires.
3. Use warm water and either a soft cloth or sponge to wash away the film of dust. For a thicker film of dust, there may be a need to use soap to avoid leaving streaks of dust when the water dries.

This will work for just about any type of solar panel, including glass or plastic-covered solar panels. It also works fine for rigid or flexible plastic solar panels. The only time where you might want to consider using a cleaning agent is for organic waste material.

Can You Clean Solar Panels With Glass Cleaner?

Glass cleaner can be used where water has not sufficiently removed any dirt on the solar panels. This could be the case with organic waste material such as bird droppings, tree sap or resin, or even pollen.

If you have ever washed a car windscreen then you will know that tree resin is notoriously difficult to wash off. Plain water might not be able to wash the adhesive sap from a tree. It is for this type of dirt that you would want to use the chemical agents in a window cleaner to break down the sap and wash it off.

Is Windex Outdoor Safe For Solar Panels?

Windex is one of several cleaning agents that are used to clean glass. It can be used to safely clean solar panels. The caveat is it should be thoroughly rinsed off to remove any residue that may reduce the clarity of the glass cover on the solar panel.

The only way to be certain is to check with the manufacturer what cleaning products can be used with your solar panels.