Clean solar panels every 3 months as a South African baseline — monthly in dusty, agricultural or high-traffic areas, and after any visible event like bird droppings, building dust or a long dry season. Panels in high-rainfall suburbs can stretch to twice a year if output holds.
Why frequency is regional in South Africa
Soiling rate follows what the air carries. Winter-rainfall coastal areas get free panel rinsing for part of the year. The inland dry season stacks dust for months with no rain to shift it. Farms add pollen, field dust and harvest debris; coastal strips add salt film; main-road rooftops add exhaust residue that rain alone does not remove.
| Environment | Cleaning interval |
|---|---|
| High-rainfall suburb | every 6 months |
| Standard urban | every 3 months |
| Dusty / dry-season inland | every 1–2 months |
| Agricultural / coastal salt / main road | monthly |
| Bird droppings present | immediately |
Droppings are not a scheduling item
A dropping is an opaque block, not a film. The shaded cell underneath resists current, heats up, and creates a hotspot that degrades the cell permanently over time. Droppings get removed when seen, whatever the calendar says.
Let output set your real interval
Inverter apps make frequency empirical. Note clear-day peak output after a clean; when a comparable clear day reads 5–10% lower with no other cause, that array has told you its soiling interval. Two or three cycles of this beats any generic schedule — including this one.
Cleaning at the right time of day
Morning and late afternoon, panels cool. Cold water on hot midday glass risks thermal shock, and the sun flash-dries water into the mineral film you came to remove — the film chemistry is in what water to use for cleaning solar panels. Technique is in how to clean solar panels, and the lost-yield cost of skipping cleans in solar panel cleaning prices.
Matching equipment to your interval
Quarterly home cleans need a brush, pole and pure water; monthly and multi-site intervals justify the rotating solar brush machines. Both ends of the range are under solar panel cleaning machines.