How Often Should Solar Panels Be Cleaned in Pretoria?

Load-shedding pushed thousands of Pretoria and Centurion homes onto solar. What most installers don't mention is that the panels need regular cleaning to keep producing what you paid for.

How much power do dirty panels lose?

It depends on how dirty they are and what the dirt is. A light film of dust might only cost a few percent. Heavy dust, pollen and bird droppings can reduce output by as much as 30%. Bird droppings are particularly bad: a single dropping can shade a group of cells and drag down the output of the whole string.

Doesn't the rain clean them?

Partly, but not well. Rain softens the dust and runs it down to the bottom edge of the panel, where it collects against the frame and dries into a crust. Gauteng's long dry winter, from about May to September, means months without rain at all, which is exactly when dust builds up most.

Recommended cleaning frequency

• Typical suburban home: 2 to 4 times a year.
• Near dirt roads, construction, farmland or open veld (Irene, Midstream, Mooikloof and similar): every 2 to 3 months.
• Under trees or where birds roost: check monthly and clean as needed.
• Best timing: late winter (August/September), before peak summer production, and after the pollen season.

The easy way to tell

Check your inverter app on a clear, cloudless day and compare it with the same kind of day a few months ago. If output has dropped noticeably and the weather is the same, your panels are probably dirty.

How to clean solar panels safely

• No high pressure. It can damage the anti-reflective coating and push water past the frame seals.
• No harsh chemicals or abrasive pads. Use soft brushes and clean water.
• Clean when the glass is cool, in the early morning or late afternoon, to avoid thermal shock.
• Stay off the panels and work safely at height. Never walk on them.

Rather leave it to us? See our solar panel cleaning service for Pretoria and Centurion.