02/04/2020

How can I keep my solar panels clean?

Low-angle view of multiple rows of solar panels in need of cleaning

How can I keep my solar panels clean? To prevent loss of efficiency, it’s important to keep your solar panels clean. The best time to clean them is in March or April. This way, your panels are clean during the sunniest months of the year, and you won’t have to worry about reduced output.

Manufacturers often say that solar panels are cleaned by rain. Since the panels are self-cleaning, manual cleaning wouldn’t be necessary. However, several studies have shown that cleaning your solar panels once a year can prevent up to 3% efficiency loss. Inspect your solar panels three times a year, and pay special attention to bird droppings, leaves, and other stubborn dirt.

Things to keep in mind when cleaning solar panels:

Clean your solar panels early in the morning or later in the evening. Water evaporates more slowly at these times, which helps to prevent lime residue.
If your roof is hard to access and you spot dirt, don’t take unnecessary risks. Preferably use a telescopic wiper and rinse the panels using a garden hose. There are telescopic wipers available that can be connected directly to a hose.
Only step onto a sloped roof if you’re wearing fall protection.
Always follow the cleaning instructions provided by the panel manufacturer.

Stubborn solar panel dirt:

First try to remove the dirt without water. If that doesn’t work and the panels are accessible, use warm water, a solar panel cleaning agent, and a soft sponge.
Avoid all-purpose cleaners or green soap, as these can damage the coating.
Don’t use abrasive cleaners, as they can harm the glass coating. Also avoid scouring sponges, which can leave micro-scratches that reduce performance. Never use a pressure washer, high pressure may force water between the glass and the cells.

Light solar panel dirt:

Don’t see any stubborn dirt and is roof access risky? Just spray the panels with a garden hose. This is a simple way to clean off dust and loose debris. If your tap water is very hard, use rainwater and a soft brush instead.