How to clean your solar sensor?

With the widespread adoption of solar panels in recent months, many are wondering if they should clean their solar panel, and how to go about it. To maintain optimal electricity production, regular cleaning is indeed necessary. But not just any old way. Since spring is a good time to do a thorough cleaning, let's take a closer look…

Why clean your solar panel?

To maintain optimal electricity production, a solar panel must be clean. Even if dirt has a limited impact, it can still reduce production by around 2 to 7%. Not to mention that a cleaned panel looks much nicer, especially with the beautiful all-black models available on the market today. Many elements can dirty the surface of the solar panel: In cities, pollution is obviously an aggravating factor. Fine particles and CO2 actively contribute to the soiling of glass surfaces, which must therefore be cleaned regularly.

In the countryside, pollen will settle on glass surfaces, especially in spring. If you're near an agricultural area, you may also have dust from plowed fields.

• Near the sea, salt and sand will obscure the solar collector.
• Not to mention the somewhat “exceptional” phenomena, such as a storm last year that brought us sand from the Sahara, leaving an orangey coating everywhere. And of course, our solar panels were covered in it. Immediate cleaning is then essential. But how do you go about it?
• Sahara sand arrived in the Centre region in March 2022. A real mess to clean…

How to clean a solar collector?

A simple soft cloth with water can do the trick (lukewarm water to avoid thermal shock on the glass). Be careful, however, not to use water that is too hard, as limescale can create a thin white layer on the glass and reduce production. Demineralized water is preferable if possible.

Do not use a Karcher-type device, whose power could damage the surface and the waterproofing of the panel. A solar collector is a set of photovoltaic cells sandwiched between two panes of glass, with a silicone seal all around.

Ground-mounted solar station: very easy to clean

If the solar collector is ground-mounted, like most solar stations such as Sunology, Beem, Sunethic, etc., it will be very easy to clean the surface with a soft cloth and water, or even a cleaning product. Since the surface is glass, we naturally think of a glass cleaner, which works very well. Personally, I use the natural product

that I introduced to you a few years ago. It works perfectly on TV screens, smartphone/tablet screens, solar panels, etc., without being harsh, since it's made entirely of natural elements. If the solar panel is mounted on a wall or roof, it can be more difficult to access. In this case, you can use a telescopic pole equipped with a broom or cleaning pad. These can be found at DIY stores or fairs. I have a 10m one that's very handy for this. It's much less dangerous than having to climb onto the roof or a ladder, not to mention the risk of damage if you step on a panel (definitely don't put your foot or knee on it!). My personal tip: I use a window cleaning robot! I spray a little product on its pads, and I use the telescopic pole to place it on the roof's solar panels. This type of robot works by preventing it from falling thanks to a suction system, and its motorized pads ensure impeccable cleaning of the entire glass surface, even on the roof. This is very difficult to achieve with a pole at arm's length. I then use the pole to retrieve it and pass it to the next panel :)

Example of a window cleaning robot. This model even sprays water automatically!

Cleaning twice a year, generally in spring and fall, is ideal (not counting the cleaning required in the event of an exceptional event like the March 2022 storm that left an orange landscape everywhere…). And ideally in the morning, before the panel has time to accumulate the day's heat: a panel can be very hot, even scorching, at the end of the day.