How often should you clean your solar panels, and does it actually matter?

How panel soiling affects solar output for Australian homeowners, how often cleaning is needed, what it costs versus what it recovers, how to tell when panels need cleaning, and whether rain alone is enough.

Key findings

• Soiling losses range from 5 to 25% depending on location. Coastal areas, farms and properties near construction lose more.
• Rain helps but doesn't fix everything, bird droppings, pollen and salt crust don't wash off reliably.
• Most Australian homes benefit from one to two professional cleans per year. Inland, dusty or flat-pitch sites need more.
• Cleaning is a modest cost against the generation it recovers. We quote per site, since roof access and panel count vary.
• Never clean panels yourself by climbing on the roof. Panels carry live DC voltage in daylight.

Does cleaning actually make a difference?

Yes, the question is how much. A panel under a thin film of dust looks fine from the ground but absorbs noticeably less sunlight. The most direct test is comparing your inverter app on a clear day before and after a clean.

Is rain enough?

For most suburban homes with pitched roofs and regular rainfall, mostly yes. But rain has limits: bird droppings create shaded hotspots, summer pollen forms a film, coastal salt crystallises, and flat roofs let water pool and leave residue.

Rain is probably enough if you are…

• In a capital city with regular winter rainfall.
• Not near farms, construction or industrial areas.
• On a steep-pitched roof with no large trees overhanging.

A professional clean adds real value if you are…

• In a dry inland location (SA, WA, QLD outback).
• Near agriculture, orchards or construction.
• On a flat or low-pitch roof, or coastal/exposed.
• Seeing visible bird activity or droppings on panels.

How to tell if your panels need cleaning

• Compare this month's generation in your inverter app to the same month last year. A gradual decline often points to soiling.
• Look from the ground, visible film, droppings or leaf debris means it's affecting output.
• Note recent weather. Four+ weeks dry in summer in a dusty area, or after bushfires/dust storms, is a sensible trigger.