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How to safely clean solar panels on your roof
Find out how often solar panels need cleaning, how to maintain them safely, and what you can do to help keep them in peak condition for years to come with this handy guide.
Solar panels are designed to last decades in outdoor conditions, so they generally require relatively little maintenance. However, depending on where you live and your solar panel set up, most solar panels will benefit from a clean once every year or two.
Here are your questions on rooftop solar panel cleaning answered, from timing to cost.
Cleaning rooftop solar panels: what you need to know
Do solar panels need cleaning?
Solar panels are designed and installed to weather outdoor conditions. They have no moving parts, so maintenance is generally minimal, and they’re usually installed on a tilt to aid dirt and water runoff. However, over time, dust, oils and bird droppings can build up.
While it’s unlikely to have a major impact in the short term, solar panels are most efficient when they’re directly exposed to sunlight. A build-up of dirt will obstruct this and, over time, could reduce the efficiency of your solar panels.
Solar panels are designed to withstand outdoor conditions. Image: Matt Harvey
How can you tell when your solar panels need cleaning?
If you can see your solar panels from the ground, simply look for any dirt, debris or a build-up of grime on your panels.
If you can’t see your panels, a drop in your solar system’s output could indicate a build-up of dirt, so keep an eye on your system monitoring.
How often should you clean solar panels?
In most cases, cleaning your solar panels every year or two should suffice. Between cleans, rain will help clean the panels naturally. However, location and panel tilt will both impact how regularly your solar panels should be cleaned.
Solar panels in dry areas, for example, usually need more regular cleaning as they receive less rain to clean the panels. Similarly, the closer you live to a busy roadway, the more dirt and grime will build up on your panels, therefore the more often you’ll need to clean them.
Most solar panels are installed on a tilt, however if you have flat (or nearly flat) solar panels, the rain won’t wash off dirt as effectively, so you’ll probably need to clean them more often.
More: Solar panel maintenance and system troubleshooting
What is the best DIY way to clean solar panels?
To prioritise safety, always clean your solar panels from the ground. It's also a good idea to turn your solar system off while cleaning.
Where possible, use a long-handled sponge or mop (you may need an extension pole) to clean your panels with clean water. You could also use a mild detergent, although water is usually sufficient and is the safest bet. Avoid any harsh chemicals or abrasive tools which could damage your panels.
Alternatively, use a dry, soft-bristled brush or broom to wipe away any debris and let the rain (or a spray with the hose) take care of the rest.
If you can’t reach your panels with a brush, giving them a light spray with a hose will usually do the trick (but don’t use a pressure washer as you risk damaging them).
The most important thing is to stay on the ground, as getting on the roof can be dangerous and is best left to professionals who have safety gear and understand different roof surfaces.
If available, check your solar user manual or manufactures guidelines for specific cleaning recommendations and/or precautions.
More: Guide to house roof leaks, repairs, maintenance and reroofing
Cleaning your solar panels every year or two should suffice. Image: Matt Harvey
Should I use a professional solar cleaning service?
If you can’t reach your panels from the ground, either with a brush or the hose, or if your panels are particularly dirty, consider paying a professional to wash your solar panels for you.
A professional solar panel cleaning service will ensure your panels get a thorough wash using appropriate cleaning equipment and safety gear.
Importantly, check your solar system warranty to make sure any work done by a professional service won’t void it.
How much does solar panel cleaning cost?
The cost of a professional solar panel clean will vary depending on the company you use, how many solar panels you have, and your home’s set up. As a guide, a standard residential solar panel clean will usually cost a few hundred dollars.
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