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Keeping Solar Panels Clean; A Maintenance Guide

By Kristy Hoare on in Solar Technology

Keeping Solar Panels Clean; A Maintenance Guide

Solar panels can last for decades, they’re built tough – but every so often, solar panels on both homes and commercial buildings require small amounts of maintenance. 

Keeping the panels free of debris and dust assures the solar power system is generating as much electricity as possible.

Even the tiniest build-up of moss, pollen or bird-droppings can lead to a serious decrease in the system’s performance. Debris can block sunlight from reaching the solar cells (where the power is generated), so keeping the panels clean allows for maximum power production and longevity of the panels.

How Often Should Solar Panels Be Cleaned?

Solar panels titled on an angle (10 degrees or more) will self-clean in the rain, removing the majority of dirt and debris. 

However, self-cleaning isn’t the most reliable way to ensure solar panels are performing to the best of their abilities.

It’s recommended that solar panels be washed once a year, but if a visual inspection shows the panels are looking clean, and if solar power production is satisfactory, then there’s no need to grab the ladder just yet – but do check again soon.

If solar panels are in a susceptible location (where dirt or grime can accumulate), then more regular inspections and washing is advised.

For example, if you live near Wellington harbor salty grime could build up regularly on the panels.


If a home has solar panels on the roof near a picnic spot, where people like to feed leftover chips to seagulls, the panels would require regular cleaning, for obvious reasons.

How to Clean Solar Panels

Cleaning solar panels with a sponge

To clean solar panels, simply scrub the panels with soapy water and a soft brush or non-abrasive sponge, then hose down to make sure the detergent has completely washed away.

Cleaning solar panels with abrasive cleaners can cause scratches on the glass panel which can affect the performance and integrity of the panel.

Solar power systems should be turned off whilst cleaning.  Ask your local solar installation company how to do this.

Remember not to walk on the solar panels and always use proper safety equipment when working on roofs.

Cleaning Solar Panels: Time To Call The Professionals?

Lack of ladder, cleaning products, or scared of heights? Best to avoid going up on the roof as it’s important to have the right equipment to do it safely. 

Cleaning companies often offer solar panel cleaning.  Ones we know of are CrestClean and WashRite.

Performance Drop Detected By Monitoring

All reliable solar power systems should come with monitoring.  Performance data can either be seen on a display via an inverter, or on a computer monitor.  Check in every month or two to make sure the solar power system is delivering as much power as expected and or desired.

If a systems performance drops (and it’s not from lack of sun) inspect potential blockages or shading on the panels.  Anything stopping light from getting to the solar cells will affect the performance of the solar panels (buildings casting shadows, tree shading etc).

Solar Power Systems That Require Less Cleaning?

Micro-inverters or solar panel optimisers can be installed with solar power systems, and will be less affected by dirt and grime when compared to a system that has a string inverter with no optimisers.


Frameless solar panels are a variety of solar panel without aluminum rods bordering the glass, meaning they are less likely to have grime build up in corners, as more dirt can slide off when it rains. 

Trina Frameless Solar Panels

Showing 1 comment

Posted by Troy From Wash Rite on 7th Aug 2022 11:34:03

Great advice and if anyone needs any help Wash Rite is always happy to help, https://www.washrite.co.nz/cleaning-service/solar-panel-cleaning-and-washing

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