Solar panels are one of the few things on a Brisbane roof that lose you money when they get dirty. A driveway with a bit of grime on it is a cosmetic problem. A solar array under a film of dust, pollen and bird mess is quietly costing you every day it stays that way.
How much output do dirty panels actually lose?
Panels work by exposing photovoltaic cells to direct light, so anything sitting between the sun and the cell reduces what gets through. In South East Queensland the usual culprits are a fine dust film that builds between storms, pollen through spring, salt haze closer to the bay, and bird droppings.
Dust builds evenly and gradually, so the drop in output is easy to miss. Bird droppings are worse than they look. A single dropping across a cell can shade it completely, and because cells are wired in series within a panel, one heavily shaded cell drags down the output of the whole string it sits in. A small mess causes a disproportionate loss.
Why Brisbane roofs get dirty faster than owners expect
Two things work against you. Our rain arrives in heavy bursts rather than steady drizzle, so a downpour moves loose dust but tends to leave a tidemark of finer material behind, and it does nothing at all to lichen or dried droppings. And a lot of Brisbane homes sit under or near mature trees, which means leaf litter, sap and far more bird traffic directly over the array.
The common assumption that the rain will handle it does not hold up over a full year.
What proper solar panel cleaning involves
This is not a job for a pressure washer. High pressure can force water past the seals around the panel frame, damage the anti-reflective coating on the glass, and in the worst case create micro-cracks in the cells that will not show up until your output drops months later. Manufacturers are generally clear that high pressure voids the warranty.
The right method is closer to the soft washing approach used on delicate surfaces: purified water, a soft brush head on an extension pole, and no detergent residue left behind to attract more dirt. Purified water matters because ordinary tap water dries and leaves mineral spotting, which puts you back where you started.
Access and safety
Most Brisbane arrays sit on pitched tile or metal roofs, often on double-storey homes. Cleaning them properly means either working from the roof with appropriate anchorage or reaching them from the ground with a pole system. Neither is worth improvising on a Saturday morning.
How often should you have it done?
For most Brisbane homes, once a year is a sensible baseline. Bring that forward to twice a year if you are under trees, near the bay, close to a main road, or anywhere with heavy bird traffic. If you can see visible marking on the panels from the ground, it is already past the point where output is affected.
A practical prompt is your inverter app. If this spring is producing noticeably less than last spring on comparable days, dirt is the first thing to rule out before you start suspecting a fault.
Getting it done alongside the rest of the roof
If your panels need attention, the roof around them usually does too. Lichen and moss on tiles will keep shedding onto the array, so cleaning the panels alone treats the symptom. It is usually more economical to combine it with a roof clean in the same visit than to book two separate jobs.
We clean solar panels across the Brisbane metro area, including Runcorn, Carindale, Mitchelton, Everton Hills, Aspley and The Gap. For a free quote, let us know roughly how many panels you have and whether the home is single or double storey.
