How to carry out a correct cleaning of photovoltaic panels

When deciding to install a photovoltaic system, it is important never to underestimate the importance of properly and constantly cleaning the photovoltaic panels.

Dirt, rain, and many other atmospheric agents can affect a system’s energy production and reduce solar panels efficiency by up to 30%.

Proper cleaning is, therefore, essential to ensure optimal and long-lasting performance.

In this article, we will address this issue and examine all the characteristics related to cleaning modules when necessary.

photovoltaic panels

Why cleaning the panels is necessary

Many external agents can affect a photovoltaic system and make it more difficult to absorb the sun’s rays, thus reducing the panels’ performance.

We find dirt, leaf residues, animal excrement, and dust among the most common. According to research carried out by the US Department of Energy, the latter can reduce a plant’s efficiency by up to 7%.

Even the rain, which partially washes the panels, contributes to the creation of stains that can reduce the system’s overall performance.

It is, therefore, essential to maintain careful control of the modules and to carry out cleaning operations.

Cleaning the panels is also part of the ordinary maintenance operations of a photovoltaic system.

Among other activities, we find:

  • Monitoring of system performance, possible through simple applications such as the Otovo App, which allows you to check the operation of the modules in real-time;
  • Corrective maintenance, which includes a series of activities to restore the plant to optimal operating status;
  • Improved maintenance, aimed at ensuring the correct functioning of all components;
  • Improved maintenance, which includes overhaul activities, to maximize performance.

When to clean?

The panels’ cleaning should take place at least twice a year (the best periods are spring and autumn).

However, it is always necessary to monitor a system’s energy production to have a concrete idea of the condition of the panels and, consequently, their state of cleanliness.

To verify the efficiency of a system, it is necessary:

  • The meter reading measures the production of electricity over a specific period. In this way, it is also possible to estimate the average daily production of electricity;
  • The reading of the second meter, the one that measures the energy not self-consumed and fed into the grid.

Annotating the data collected from these readings allows you to create a history to verify the system’s efficiency and the need or not for cleaning and maintenance operations.

How are the panels cleaned?

For cleaning the panels, specialized companies use demineralized water or water deprived of any impurities so that the dirt is trapped in the best possible way and removed naturally.

The use of demineralized water allows not having to perform any rinsing of the panel, thus guaranteeing the operator minimum effort and maximum yield.

Special brushes are then used, which, by creating a pressure/depression effect on the panel, permanently remove the dirt from the glass.

It is a completely ecological cleaning system, which avoids polluting chemical products and thus contributes to protecting the environment.

clean solar panels

In addition to cleaning all the components, the company you rely on is required to carry out further operations:

  • A complete inspection of all parts of the system to check for any internal deterioration;
  • Checking the wiring and electrical connections;
  • Voltage check.

How much does it cost to clean solar panels?

For cleaning solar modules, the average cost is between 40 cents and €2 per square meter (m²).

If a plant is located on a very high roof, which is difficult to reach, those responsible for cleaning will have to use a lift or a mechanical arm, which can cost between €15 and €40 per square meter (m²).

Where to buy solar panels? You can buy solar panels from online retailers such as Amazon, eBay. Many solar panel manufacturers sell their products directly to consumers. Some popular manufacturers include Renogy, SunPower, and LG Solar.

Amateur cleaning

Relying on specialized companies for cleaning the panels is essential. However, it is possible to do a little do-it-yourself cleaning to monitor the level of cleanliness more frequently, pending expert intervention.

If you decide to carry out an amateur cleaning, it is important to remember that the best time to act is the early morning hours, as the dew helps soften the residues that have been deposited.

There are also numerous kits on the market for cleaning the panels, at the cost of around €400, which contain:

  • A telescopic rod;
  • A filter to produce purified water;
  • An adjustable angle adapter to achieve any angle;
  • A hose;
  • A brush with fixed and soft bristles.

Keeping the panels of a system properly clean is an operation that should never be forgotten and can make a difference in the long run.

SandStorm, the robot that cleans the panels

SandStorm, the robot that optimizes energy production in large photovoltaic systems, was created by Reiwa Engine, an innovative company based in Vittoria (in Ragusa). SandStorm was created to provide a solution to a simple but, at the same time, complex problem: the manual cleaning of photovoltaic panels.

The robot can clean surfaces for tracker structures with slopes of up to 12 degrees, jumping from one row of panels to another and guaranteeing effectiveness even on surfaces with marked slopes.

Amateur cleaning

Currently, the experimentation involves a small portion of plants to test the effectiveness of the new dry, automatic, and daily method. The challenge is to engineer a continuous cleaning process, which feeds itself thanks to the energy produced by the ground mounted solar panels and does not require operator intervention.


Ensuring maximum efficiency allows us to produce more clean energy for the home, thus helping to do good for our environment and, above all, for our wallet!

Frequent questions

How do you clean photovoltaic panels?

The photovoltaic panels are cleaned using demineralized water and special brushes, which, by creating a pressure/depression effect on the panel, permanently remove the dirt from the glass.

How often should photovoltaic panels be cleaned?

The cleaning of the photovoltaic solar panels by specialized companies should occur at least twice a year.

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