Your winter was wet, and your roof collected a season's worth of debris between June and September. Now that the sun is climbing higher every week, the grime on your solar panels is blocking the sunlight you paid for.
To get the most out of your solar panels, you need to learn how to clean solar panels. This is not a job to rush, or do on a wet roof, or with the wrong tools. Our team has developed a method for cleaning solar panels, based on ten years of experience installing and maintaining Solar Photovoltaic systems in the Winelands and the Cape.
What Winter Leaves Behind On Western Cape Panels
The type of dirt that accumulates on solar panels varies by region. In the Western Cape, three main factors contribute to the grime. First, winter rain splashes soil and roof grit onto the lower rows of panels, where it dries into a stubborn film.
Second, spring pollen from orchards, vineyards, wheat fields, and fynbos settles on the panels. Third, the south-easter blows fine dust across the Peninsula and the Boland from October onwards, so even clean panels do not stay clean for long.
Coastal homes also have to deal with salt haze, while farms have to contend with bird droppings and lichen. All these substances create shade, which reduces the panel's output.
How To Clean Solar Panels Safely: Before You Climb
The biggest risk when cleaning solar panels is not the panels themselves, but the roof. Before you start, assess whether you can reach your solar array from the ground or from a stable ladder on firm, level footing.
If your system is on a steep pitch or a double-storey roof, or if the tiles are loose, do not attempt to clean the panels yourself. The risk of falling is too great.
If you can access the panels safely, choose your timing carefully. Clean the panels early in the morning or late in the afternoon, when the glass is cooler.
Switch off the system at the DC isolator and the AC breaker, if you know how to do so. Your panels still generate voltage in daylight, so you want to avoid working with live connections and water.
The Step-By-Step Method That Will Not Scratch The Glass
To clean your solar panels, follow these steps. Start with a soft rinse using a hose on a gentle setting. Never use a pressure washer, as it can force water into the frame seals and junction boxes, and chip the anti-reflective coating.
Next, use a soft brush or a sponge on a telescopic pole with plain water. Work from the top of the panel downwards, so the dirt runs off rather than back across the glass. Pay special attention to the lower edge, where the winter mud line sits.
If some dirt will not shift, use a small amount of mild dishwashing liquid in a bucket of water. Avoid using abrasive pads, scourers, solvents, or household glass cleaners, as they can leave residue or micro-scratches.
Rinse the panels thoroughly, then let them air dry or squeegee them gently if you can reach safely. Finally, inspect the array as a whole, to make sure all the panels are clean.
When To Leave Panel Cleaning To The Professionals
Some jobs are best left to trained professionals with the right equipment. If you notice any of the following, book a visit instead of trying to clean the panels yourself: cracked or discoloured glass, loose cabling, a panel that looks darker than its neighbours, lichen or bird mess that has baked on over several seasons, or a roof you cannot reach from a stable ladder.
A professional clean also includes a system inspection, where our technicians check the mounting hardware, cable integrity, inverter readings, and your monitoring data. For businesses and farms with large arrays, this combined service is the best way to protect the warranty and the return on investment.
Internationally, the industry is investing in waterless and robotic cleaning solutions for large solar farms, particularly in dusty, water-scarce regions. However, for rooftops like yours, careful manual cleaning and scheduled professional services remain the best approach.
Why Clean Panels Matter For Your Summer Savings
Clean solar panels produce more electricity, which means you do not have to buy as much from Eskom or your municipality. For homeowners, this can lead to annual savings of up to 70%, depending on usage and system design.
For farms and businesses running hybrid systems, clean panels mean the batteries fill earlier in the day, and the grid or generator kicks in less often. Cleaning your solar panels is not a separate chore, but part of your investment. Knowing how to clean solar panels, or knowing when to hire a professional, is what keeps your system performing well.
Book Your Spring Panel Clean With Winelands Solar
If your roof is safe and your array is small, follow the steps above this month, before the south-easter settles in for summer. If your roof is steep, your system is large, or you have not had an inspection since installation, let our team handle it.
Visit winelandssolar.co.za or call our office to book a spring cleaning and inspection for your home, business, or farm. We will confirm your system is clean, compliant, and ready for peak sun. We have been delivering sustainable, efficient, powerful, and reliable solar systems across the Western Cape for ten years.
Sources available on request.
