What's involved
Why it matters
Rain rinses loose dust off the middle of a panel and leaves a tide line of concentrated dirt along the bottom edge — exactly where the lowest row of cells sits. It does nothing at all to bird droppings or lichen. From the ground, none of that is visible.
Soiling costs you output, and how much depends entirely on what is on the glass. An even film of dust dims a panel a little. A hard spot blocks the cell underneath it completely, and one shaded cell drags down the whole string it sits in. That is why a few droppings cost far more than their size suggests.
Order matters if you are bundling the work. Roof cleaning first, gutter cleaning next, panels last — so nothing washing off the roof lands on freshly cleaned glass.
Worth understanding
Toowoomba sits at about 700m on the Great Dividing Range. Fog, heavy dew and cool nights mean lichen and algae take hold on panel frames and the edges of the glass the same way they do on a roof. Rain will not shift either.
Then there is the dust. Agricultural dust off the Downs settles as a fine film that rain smears rather than washes. A shower can leave the glass looking worse than it did before it rained.
Panels on a shed or a rural block near cropping country cop both at once. Most manufacturer warranties rule out abrasives, harsh chemicals and pressure washing, which is precisely what we do not use. Detergent leaves a residue that attracts dust. Abrasives scratch the anti-reflective coating and cut output permanently. High pressure stresses frame seals and can force water into the junction box.
Once a year suits most Toowoomba homes. Twice if you are near cropping country, under trees, on an unsealed road, or if birds have got in under the panels. Check your inverter app across a few clear days either side of a clean and you will know what your own array needs.
Not sure it stacks up for your place? Read is solar panel cleaning worth it, or check our insurance and compliance if you want the paperwork first.
Common questions
Yes, and the size of it depends on what is on the glass. A light, even film of dust costs relatively little. Bird droppings, lichen and the baked-on agricultural dust that blows across the Downs are a different problem, because they block cells completely rather than dimming them. A shaded cell drags down the whole string it sits in, so a few hard spots cost far more output than their area suggests. More on whether it is worth it.
Two local causes. Agricultural dust off the Downs settles as a fine film that rain smears rather than washes, and the Range climate — fog, dew and cool nights at 700 metres — grows lichen and algae on panel frames and edges the same way it does on roofs. Panels on a shed or a rural block near cropping country cop both at once.
Not properly. Rain rinses loose dust off the middle of a panel and leaves a tide line of concentrated dirt along the bottom edge, exactly where the lowest row of cells sits. It does nothing at all to droppings or lichen. Panels that look clean from the ground frequently are not.
Pure deionised water and a soft brush. No detergent, no abrasive, no high pressure. Detergents leave a residue that attracts dust and can void panel warranties. Abrasives scratch the anti-reflective coating and permanently reduce output. High pressure stresses the frame seals and can force water into the junction box. The boring method is the correct one here.
Not when it is done this way. Most manufacturer warranties specifically rule out abrasives, harsh chemicals and pressure washing, which is precisely what we do not use. If your manufacturer specifies a particular cleaning method, tell us and we will follow it.
Once a year for most Toowoomba homes. Twice a year if you are near cropping country, under trees, on an unsealed road, or if birds have found the gap under the panels. A quick look at your inverter app across a few clear days either side of a clean will tell you what your own array actually needs.
Yes. Crew are Working at Heights certified, the job runs to a documented safe work method statement, and TopWash carries $20 million public liability. Panel cleaning is the job where homeowners most often decide to have a go themselves, and a wet panel on a pitched roof is about as slippery a surface as exists on a house.
A great deal. Pigeons nesting in the cavity between panel and roof build up droppings and nesting material that block airflow, corrode the roof sheet and create a real fire and vermin problem. We will inspect and report on it as part of the clean, and tell you whether mesh proofing is worth doing.
Yes. You get a condition report on the glass, the frames, the seals, the mounting rails and any visible cabling, with photos. We are not electricians and we do not touch the wiring or the inverter, but you will know if something up there needs a licensed installer to look at it.
Still not sure what your array needs? Request a free quote, check the areas we service, or call James on 0490 397 740.
Pricing
Free quotes, and we quote the job rather than an hourly rate. Photos of the roof and the array are usually enough to give you an accurate figure.
In their words
★★★★★
James from Topwash provided excellent communication and professionalism when engaged to clean the roof of our family home in Highfields. James discussed what options we had to undertake the cleaning of the roof that was covered in dirt, moss and Algae, not an easy task however an excellent job was completed. We would highly recommend Topwash.
★★★★★
James did an excellent job of cleaning our roof. He was polite and efficient and turned up when he said he would. We are happy to give Top Wash Exterior Cleaning 5 stars.
Get in touch with James
Tell us how many panels there are, what the roof is made of, and whether anything has got in under the array. We quote the job, not an hourly rate, and the quote costs you nothing.
Doing the roof at the same time? See roof cleaning →