Solar power systems generate electricity with no moving parts, which means they have simpler maintenance requirements than other power generation systems. For example:

• PV modules do not have spinning blades and gearboxes like wind turbines, nor are they exposed to fossil fuel combustion at high temperatures.
• But since solar panels don’t move, dust and other particles can accumulate more easily on their surface.

If dust build-up blocks 50% of the sunlight reaching your solar panels, their energy output can drop by half. This decrease in productivity can negatively affect electric bill savings — if you were previously saving $100 each month, you might notice that savings drop to around $50 a month.

Regular cleaning helps keep your solar panels operating at optimal capacity, which means your system generates its expected electricity output. A dirty solar energy system does not operate at maximum efficiency, which can result in higher power bills and, as a result, a longer payback period. Professional solar panel cleaners use the term “soiling losses” to describe the efficiency loss caused by dust and dirt buildup on your PV system.

Understanding Solar Panel Components

Solar panels consist of photovoltaic cells fully encapsulated by other materials, which prevents exposure to dust, dirt, bird droppings and weather conditions. However, grime can accumulate on external surfaces over time, which you should clean regularly. Here are some tips to clean different solar panel components:

Cleaning the Glass Cover

A transparent glass cover protects the PV cells in a solar panel. Ideally, you should clean the glass surface with non-abrasive cleaning tools like a soft bristle brush or squeegee. Avoid using wire brushes, roof rakes or any other tools that may leave scratches.

You can wash solar panels with a garden hose, but you should never do this when they are hot since the drastic temperature change can crack the glass. Keep in mind that solar modules may still be hot after sunset, especially on summer days.

Make sure you have a clean water supply when cleaning your panels. Washing your panels with hard water will leave behind a mineral layer after the water evaporates, defeating the purpose of the cleaning process.

Cleaning the Aluminum Frame

Solar panels have an aluminum frame that holds all other components together. Solar manufacturers use powder coating and other treatments to improve corrosion resistance, making the aluminum frame suitable for outdoor use. However, the frame is constantly exposed to dust, just like the glass cover.

Since the aluminum frame is corrosion-resistant, you can wash it safely with a standard water hose. Never use a pressure washer: it can damage the seals around the aluminum frame, and you may void the product warranty. Cleaning solutions with detergents or other chemical agents can also damage the seals and should be avoided.

If your panels have not been cleaned in a long time, washing may not be enough to remove grime. In this case, you should brush away dried-up dirt before using a hose. You should avoid chemical agents in general but can use a small amount of soapy water to clean spots with excessive dirt buildup.

Cleaning the Polymer Backsheet and Junction Box

The back of a solar panel is covered with a backsheet, typically made of a durable polymer. The back surface also contains a junction box with electrical terminals used to wire multiple panels into a string circuit.

Since the backsheet and junction box are not always outward facing, these components require less cleaning than a panel’s glass cover and aluminum frame.

• In rooftop solar installations, the backsheet and junction box are hidden by a small gap between the back of your panels and the surface of your roof. This positioning creates minimal exposure to dust and dirt.
• But a ground-mount system or solar carport exposes your panels to dust from all directions. In this case, the back surface may also need frequent cleaning.

You can follow the same cleaning recommendations for the glass cover and aluminum frame to clean the backsheets. Soft brushes and non-pressurized water are suitable, but avoid pressure washers and chemical agents.

Conclusion:

Never open the junction boxes or manipulate electrical connections in any way. If your solar installation includes a workmanship warranty, you can contact your provider to inspect any electrical malfunctions. Many companies also offer professional solar panel cleaning services.