Solar panel cleaning by the experts.

No, never use a pressure washer. The high water pressure can damage the seals around the cells, wear down the anti-reflective coating and cause micro-scratches you can’t see with the naked eye. Water can also be forced under the panels and into the wiring, causing a short circuit. Instead, use a soft brush with pure water or call in a professional.

Pure water contains no minerals or limescale. Tap water contains limescale and minerals that leave white streaks and spots on the glass as it dries. That residue reduces light transmission and attracts new dirt faster. Pure water dries completely streak-free, so your panels stay clean for longer and capture as much sunlight as possible. Read more about cleaning solar panels with pure water.

That depends on your manufacturer and the method you use. Most module manufacturers explicitly exclude damage caused by improper cleaning from their warranty, such as damage from pressure washers, abrasive products or harsh chemicals. A professional clean with pure water and soft brushes does meet the conditions of all major manufacturers. Always keep your cleaning report as proof in case you ever need to make a warranty claim.

Hotspots are areas on a solar panel that overheat locally because part of a cell is covered, for example by stubborn bird droppings, leaves or moss. The covered cell no longer produces energy, but it still has to carry the current from the other cells. That creates resistance and heat, and over time the cell can be permanently damaged. Regular cleaning removes the dirt that causes hotspots. During a professional clean, we also detect existing hotspots with a thermal imaging inspection.

No. Household cleaning products such as Dreft washing-up liquid, soft soap, all-purpose cleaner and car shampoo attack the dirt-repellent coating on the glass. As a result, dirt actually sticks faster, your yield drops and the surface becomes more prone to scratches. Abrasive cleaners and scrapers are a no-go as well. Only ever clean your panels with pure water and a soft brush or sponge. Also read our article on cleaning solar panels with Dreft.

The best season is early spring (March–April), just before the sunniest months, which account for around 70% of your annual yield. Ideally, clean early in the morning or on a cloudy day. In full sun the water dries too quickly and leaves spots. Panels in the sun also get extremely hot: cold water on a hot panel can cause thermal shock and micro-cracks.

There are three signs. Visual: you see a grey haze, spots, bird droppings or a green film on the glass. In your monitoring app: the performance ratio gradually drops compared with similar days or years. And after unusual conditions, such as a Saharan sandstorm, a prolonged drought or construction work nearby. Not sure? Send us a photo of your installation via the quote form and we’ll give you free, no-obligation advice.